Logger: add a way to filter logs

[Heziode]

I do not find a way to filter result of logs.

For example, I want a file foo.adb to be in INFO or completely disable it, and a file bar.adb with a DEBUG severity.

Currently, all units are in DEBUG verbosity, and it is quite difficult to debug with the amount of log.

[Heziode]

Found my answer here: https://ada-util.readthedocs.io/en/latest/Util_Log/#log-configuration