train-sim: initial commit

[Castavo]

closes #6993

This adds the train-sim subfolder to the project !

I added @OpenRailAssociation/osrd-core as maintainers. There will be probably very much to discuss please don't hesitate

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 10.88%. Comparing base (1342dc0) to head (8a493c6). Report is 67 commits behind head on dev.

:exclamation: Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@              Coverage Diff              @@
##                dev    #7193       +/-   ##
=============================================
- Coverage     28.15%   10.88%   -17.27%     
=============================================
  Files          1110      601      -509     
  Lines        139243   100424    -38819     
  Branches       2780      930     -1850     
=============================================
- Hits          39198    10928    -28270     
+ Misses        98438    88571     -9867     
+ Partials       1607      925      -682     

Flag	Coverage Δ
core	?
editoast	?
front	9.11% <ø> (+0.10%)	:arrow_up:
gateway	2.45% <ø> (ø)
railjson_generator	87.49% <ø> (ø)
tests	83.96% <ø> (-0.02%)	:arrow_down:

Flags with carried forward coverage won't be shown. Click here to find out more.

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.