Remove unnecessary Hlt and L0 decoding sequences

The HLT decoding in DecodeTriggerSeq was redundant because it is already done in the filtering sequences when required. Similarly, the L0 decoding was unnecessary except when asking for RecL0Only. This MR:

• Removes the DecodeTriggerSeq
• Runs the L0TriggerSeq directly as a PhysicsSeq member, only if RecL0Only is set
• Throws an Exception if L0 filtering is requested in Upgrade configuration
• Provides a (temporary) update to BrunelExclusions.py to avoid all tests failing due to the above changes

A side effect of this MR is that simulation tests running on datasets in which the Hlt was not applied and that were printing WARNING HltDecReportsDecoder:: Could not find HltDecReports raw bank. Returning empty HltDecReports will now fail because the warning has gone, so their references should be updated

Another nice side effect is that we no longer access the HltTCK config.cdb in simulation jobs.

- PropertyConfigSvc    INFO  resolving alias TCK/0x########
- ConfigCDBAccessSvc   INFO  opening DBASE/TCK/HltTCK/vXrYpZ/config.cdb in mode ReadOnly
- PropertyConfigSvc    INFO  resolved TCK/0x######## to 00d005885a31707bb508cc3e55567c22

This MR should be propagated to all maintained -patches branches and master

@rmatev FYI