CI pipeline optimization

Resolves #46 and #40.

The average pipeline time is ~11 minutes until failure or success with the current CI configuration. Main causes of this are:
- The original Docker image used for the runners (`lycantropos/cmake`) is bloated, weighing at about **600 MB** for the [latest tag](https://hub.docker.com/r/lycantropos/cmake/tags). This image is downloaded for every stage of the pipeline separately, and due to its size, there is a huge delay between setup and start of the stage.
- There are too many calls to `apt-get update` and `install`, that are executed at every stage without reason. Plus, downloading and installing additional packages *for every stage* is also time-consuming, which contributes to the delays.

This problem is solved by creating a lighter Docker image (`lightspot21/acubesat-ci`), based on Alpine Linux, which contains all the necessary tools for linting and building (`cmake`, `cppcheck`, `clang-tidy`, `gcc`, `vera++`) plus the code coverage tools `gcovr` and `lcov`. The whole package weighs at **168 MB** for the [latest tag](https://cloud.docker.com/repository/docker/lightspot21/acubesat-ci/tags), which is **73%** less than what we use currently.

Gains:
- Average pipeline time down to **5-7 minutes** from 11-13 (variation is due to server load) with some times even earlier when failing, resulting in quicker fixes.
- Ability to directly control tool versions.

All comments/ideas are welcome, especially on optimizing the Docker image size even more!

See merge request acubesat/obc/ecss-services!51

Reenable clang-tidy on new pipeline

Fix vera and clang-tidy

Update the used Dockerfile to include clang-tidy

Clean up commented out stuff from CI configuration

Update Dockerfile according to suggestions

Fix the virtual package

Move update to initialization to ensure latest version of everything

Merge branch 'faster-ci' of https://gitlab.com/acubesat/obc/ecss-services into faster-ci

Fixes for new broken clang-tidy rules

# This is the 1st commit message:
Add the Dockerfile used to generate the image
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Reenable clang-tidy on new pipeline
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Fix vera and clang-tidy
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Update the used Dockerfile to include clang-tidy
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Clean up commented out stuff from CI configuration
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Update Dockerfile according to suggestions
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Fix the virtual package
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Move update to initialization to ensure latest version of everything

Fix missing script directive

Update .gitlab-ci.yml

Override image entrypoint to include '-c' argument

Revert previous override due to broken .gitlab-ci.yml

Remove -Werror argument

Update .gitlab-ci.yml

Update doxygen configuration

See merge request acubesat/obc/ecss-services!42

A small string overhaul

This commit adds functions to:
- Append strings of fixed size
- Read strings with or without a trailing `\0`

There is also a string-related fix for the function management service.

This takes care of issues #43 and #11.

Don't mind the irrelevant commits, they show up because `ci-1` is not merged to master yet.

See merge request acubesat/obc/ecss-services!41

Fix cppcheck errors

Fix pipeline issues.

See merge request acubesat/obc/ecss-services!43

Fix the build

This MR:
- fixes a regression with the new version of cppcheck (`1.88`) on some testing code
- disables the 13.4 MISRA rule due to a false positive
- removes the clutter created by .dump files

See merge request acubesat/obc/ecss-services!40

Show less of the irrelevant files, and use the correct link in the README file

ECSS ST13 Split Function

**ECSS ST13 Split Function**  
After the initial development of the ECSS ST13 Large Packet Transfer Service, it is time to * *drumroll* * add the required function that is used to split the Large Messages into smaller ones.  
Currently it works with normal messages. However, the function should be changed in the future, perhaps with the addition of messages that are able to contain an amount of data larger than the current Message class can hold. Right now the Message::data can contain up to 1024 bytes. The max octet string size is 256. The testing was based on these numbers.

**Things to consider about this Service && Function**
*  A new class that fosters all the needs of a large message might be needed
*  Sensors or any device that will produce any kind of data, might use this class, for the purposes of ignoring the data size limit imposed by the protocol

See merge request acubesat/obc/ecss-services!37

Maybe a thrown error isn't displayed: https://trac.cppcheck.net/ticket/5746

Keep both time formats

The CUC time format has been added to the `TimeHelper`. So, we have two possible time formats: the CUC (TAI compliant) and the CDS (UTC compliant), that are described in [CCSDS 301.0-B-4 ](https://public.ccsds.org/Pubs/301x0b4e1.pdf).

See merge request acubesat/obc/ecss-services!36

Automatic per branch, code coverage report and documentation generation

## Summary
In this request a page deployment job is added to CI settings, which takes care of the automatic, per branch, generation of the code coverage and the doxygen based documentation.

## Implementation details
To generate the code coverage reports, two main additions where needed. First the `set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g -O0 -Wall --coverage")` compilation flag was added in the `CMakeLists.txt` file, in order to generate the tests with no optimization and also add the necessary coverage - `.gcno` - files. The second addition is the [`gcovr`](http://www.gcovr.com/en/stable/) package, which is a python based package to generate code coverage reports and create the html page.  
In addition to code coverage, in this request the automatic generation of the doxygen documentation is also implemented.  
Once this is merged, there will be one page per branch for the documentation and one for the coverage report. The pages will have the following form:  

**Coverage:** `https://acubesat.gitlab.io/obc/ecss-services/coverage/<branch-name>/`  
**Coverage in master:** `https://acubesat.gitlab.io/obc/ecss-services/coverage/`  
**Documentation:** `https://acubesat.gitlab.io/obc/ecss-services/docs/<branch-name>/`  
**Documentation in master:** `https://acubesat.gitlab.io/obc/ecss-services/docs/`  

## Future improvements and ideas
* The coverage page look can be improved using custom styling, so one goal is to improve the coverage page look.
* Add a welcome page in the root page `https://acubesat.gitlab.io/obc/ecss-services/`

## Update (05/04/2019)
Major improvements have been made since the creation of this merge request. Code coverage is now generated by using two tools, [`gcovr`](http://www.gcovr.com/en/stable/) and [`lcov`](http://ltp.sourceforge.net/coverage/lcov.php). They are used together to compare each other and also generate a better version of the code coverage. Adding to that, the coverage argument hασ been moved from the `CMakefile.txt` to command line arguments like `cmake . -DCMAKE_CXX_FLAGS="-g -O0 --coverage"`.

See merge request acubesat/obc/ecss-services!34

- Improved the overall look of the page
- Coverage generation using lcov and gcov
- Using less gitlab server page by removing interjob artifact generation

Execute TC packets

Closes #31. Actually, `execute()` functions receives as input TC packets and they call the proper services'          functions that have been implemented to handle TC packets.

See merge request acubesat/obc/ecss-services!35

Keep consistent the declaration of the execute functions in all child classes and change the scope of the execute function in the MemoryManagementService

Ecss st19 array replacement

etl::map was used to replace the array that was used to store the EventActionDefinition struct. 
Also, in this branch ErrorHandler error throws were added.

Thanks to @lightspot21 for the input.

See merge request acubesat/obc/ecss-services!33