Add new style configuration for Pixel and TRT digitization, with tests and inclusion in the joint digitization test.
Add MOD_ItemList functions for InnerDetector and MuonSpectrometer modules, towards use with OutputStreamCfg.
OutputStreamCfg currently does not merge correctly (see !23028 (merged)), so its uses are left with FIXME comments.
Clean up old tests.
This supersedes !23047 (closed).