Large merge to import TrigInDetAnalysis changes from final 21.1-dev to 21.3

Includes the merge of code from last version of 21.1-dev to 21.3, so all functional changes were already reviewed and fully validated when in the initial MR for 21.1-dev so we don't need these reviewed again, and just need to see the output from the validation to determine whether this sync has worked.

These functional changes include addition of a new header file required for matching the full trigger objects with the tracks needed for the full object selection

Additional changes not from 21.1-dev includes some tidy up of the comments.

Since it was merging 21.1-dev without the copyright, decided to use the opportunity to modify all the file head comments to be more properly doxygen compliant as suggested in the coding guidelines. Also updated the year from 2018 to 2019 since I was here.

There are also many other code compliance cosmetic changes, eg replacing all the __FILENAME_H with PACKAGE_FILENAME_H in the include guards and so on/

As this is such a large set of changes there will inevitably be some code guidelines compliance issues that have been missed. I would prefer to merge the ones that we have now, and then fix the rest in additional merge requests over the coming days.

These changes are to some extent further discussed in ATR-19009 which these changes partly address.