Rename `ConfigFlags.Detector.(Pixel/SCT/TRT)On` to  `ConfigFlags.Detector.Reco(Pixel/SCT/TRT)`
to make the meaning of the flag clearer. Add `ConfigFlags.Detector.RecoIBL` as discussed.

After adding some additional protections, the `testAllConfigFlags_EVNT` unit test
should now also pass in the AthGeneration project.

In this way it will only be loaded when required improving making
it easier to use ComponentAccumulator in the AthGeneration project.

Code should work with both py2 and py3 as long as we're
doing a py2 build.

With athenaMT it is best to rely on the default (ROOT) signal handler in
CoreDumpSvc, which uses gdb to produce the stacktrace for all threads.
Setting `FatalHandler = 438` makes use of the `SealSignal` handler,
which only produces one trace. For production environments where the gdb
traces are not needed, one should override the setting in the transform
or AMI tag as is already done today.

Relates to ATEAM-629.

appendCAtoAthena: Recusive conversion of GaudiConfig-ListHelper to list, do not append duplicates to SvcMgr, ToolSvc, etc

collections.Sequence is deprecated as of python 3.3, and removed in 3.9.

Reverse use of context in JetBTaggingAlg for JFVtx and SecVtx container (crash with ctx)

Need to flush output in order to get consistent output ordering
between py2 and py3.