TriggerJobOpts: make runHLT the main CA config module

This is a major rewrite (and in fact replacement) of runHLT_standalone_newJO.py, which is replaced by the runHLT python module. It is supposed to be usable in athena and athenaHLT via different entry points:

> athena --CA [options] TriggerJobOpts/runHLT.py [flags]
> athenaHLT [options] TriggerJobOpts.runHLT [flags]

(the athenaHLT syntax requires !63458 (merged))

In detail:

• The content of runHLT_standalone_newJO.py has been moved to runHLT.py and where necessary split into an athena(HLT) specific part.
• The common part is in the runHLTCfg function, which is the one that should be modified in almost all cases.
• All flags are set in one set_flags function.
• runHLT_standalone_newJO.py is kept as a wrapper until all references to it have been changed (documentation, ART).

Modulo the name change of the job options, there should be no visible change to the user in athena. It does not yet work in athenaHLT and will require further changes.

Since we are going to be using this for the next few years, any feedback on the interface would be very welcome.

cc @wiedenma @mark @tbold @stelzer @fpastore @smh @jmasik

Relates to ATR-26582.