Categorise messages found by log checker

We had some confusion figuring out which messages were causing test failures, e.g. on ATR-29493.

This change builds some more categorisation into the log file checker, so that it communicates more clearly which messages fall into which categories, but is also a little more explicit that all printed (i.e. not ignored) messages are actually prohibited and responsible for the test failing.

E.g. taking the JIRA noted above, the check run on athena.merged.log goes from reporting:

Ignoring warnings/error patterns defined in checklogTrigP1Test.conf
Ignored:

Found 3 error/warning message(s) in athena.merged.log:
02:32:20 xAOD::AuxSelection WARNING Selected dynamic Aux atribute "BadChannelList" not found in the registry
02:32:20 xAOD::AuxSelection WARNING Selected dynamic Aux atribute "NCELL_SAMPLING" not found in the registry
02:32:20 xAOD::AuxSelection WARNING Selected dynamic Aux atribute "SECOND_TIME" not found in the registry
FAILURE : error/fatal found in athena.merged.log

to

Ignoring warnings/error patterns defined in checklogTrigP1Test.conf
Found 3 prohibited message(s) in athena.merged.log:
02:32:20 xAOD::AuxSelection WARNING Selected dynamic Aux atribute "BadChannelList" not found in the registry
02:32:20 xAOD::AuxSelection WARNING Selected dynamic Aux atribute "NCELL_SAMPLING" not found in the registry
02:32:20 xAOD::AuxSelection WARNING Selected dynamic Aux atribute "SECOND_TIME" not found in the registry
Ignored:


FAILURE : problematic message found in athena.merged.log

It's a subtle change (would be more substantial if a larger variety of bad messages were found), but it avoids the disconnect between reporting WARNING messages, and then failing with a error/fatal message.