in order to make construction and adding more natural

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

Changed comments

Fixed names in ErrorHandler and enumeration of errors and removed explicit declaration of true or false in a CHECK

- changed variable names
- added breaks
- corrected a comment
- deleted explicit declaration of true/false in ifs
- fixed a bug in tests caused by passing the message by reference

- Changed disableEventActionDefinition
according to the needs of multimap
- Added errors in ErrorHandler

- Changed deleteEventActionDefinition
according to the multimap needs

- Added a new variable eventActionDefinitionID
- Added the size of the multimap as #define in ECSS_Definitions.hpp

Changed the way add action-definition function works after rechecking the standard and updated the corresponding tests as well as added documentation in those tests

# Conflicts:
#	CMakeLists.txt
#	src/Services/EventReportService.cpp