Verify if the submitted manifest YAML is consistent with the git repository

[iszulcdeepsense]

Racetrack could check if the submitted manifest.yaml is consistent with the one found in the git repository of the Job's source code.
Discrepancies may happen, if someone forgets to push the local changes to git repository. A sort of warning would prevent from such inconsistencies.

Notes:

• this may be an optional setting that will be enabled on test/preprod/prod environments
• this may also check for not-pushed / dirty state of repository (in general, output of git status should be Your branch is up to date and nothing to commit, working tree clean)