Refactor collection of debug and trace tags (#5996)

Refactor collection of debug and trace tags (#5996)

We have a mechanism to collect all debug and trace tags used throughout the code base to allow checking for valid tags.
This mechanism relies on a collection of more or less readable shell scripts.
#5921 hinted to a problem with the current setup, as it passes all source files via command line.
This PR refactors this setup so that the scripts collect the files internally, and only the base directory is passed on the command line.
As I was touching this code anyway, I ported everything to python and combined it into a single script, in the hope to make it more maintainable.
Fixes #5921.