CITest: migrate Egamma CI tests
Migrate the following Egamma CI tests to new testing framework:
- https://gitlab.cern.ch/atlas-sit/CI/-/blob/master/TestConfig/EgammaTest_optional.citest
- https://gitlab.cern.ch/atlas-sit/CI/-/blob/master/TestConfig/Egamma_CAConfig_required.citest
The old tests will be disabled ~24 hours after this MR has been merged and any updates for the master branch need to be done within the CITest package (cc @christos).
Relates to ATLINFR-4360.