LArRegionSelector+RegionSelector: Cleaning up use of LArCablingLegacyService.

Cleaning up use of LArCablingLegacyService, so that it can be deleted.

Change from using the LArRoI_Map tool to the LArRoIMap conditions object. Can then remove dummy dependency on LArOnOffIdMapping.

Don't write anything at INFO level from a component constructor --- otherwise we get ugly output during genconf.

Add dependencies to the configuration to configure the LArRoIMap conditions algorithm.