Lock the addon files to this specific commit in order to avoid breaking stuff if cppcheck updates without prior creation of a package by Debian

Attempt to fix the segfaults that showed up

Fix escape codes and a syntax error in the for-loops

Add a line feed to `do` so that Bash stops whining

Update ci/cppcheck.sh

Fix segfaults, attempt #2

Update cppcheck to version 1.86-1

Fix the for loops

Add `helit` tag to run on local CI

- Fixed clang-tidy version
- Moved CI to separate .sh files