Fix logging yet again

[kba]

This PR is an attempt to fix a lot of code smell related to logging.

• getLogger will raise an exception if initLogging was never called before getLogger before initLogging will emit CRITICAL log messages about that fact and the file/line where it originated
• setOverrideLogLevel can now happen before initLogging (cmdline loglevel override does not work anymore #597)
• new method disableLogging which requires a new initLogging call and resets override loglevel
• no longer set the loglevel of the root logger to logging.NOTSET
• no more module-level loggers - use method-specific loggers (which can re-use the same name of course)
• use the first config file found xor the builtin config. setOverrideLoglevel should take precedent over either.

Since logging happens in many places, PR is probably better digestable commit-by-commit.

[bertsky]

This clearly moves into a good direction. I must confess though that I do not grasp this fully. For example, I don't get why reinit=True is necessary for each initLogging call in the various CLIs. (Shouldn't the overrideLogLevel be restricted to only set the global variable for getLogger, and unset any existing log levels?)

Note that in my review I went through each commit individually, so some of the comments don't apply after a later commit anymore.

[codecov-commenter]

Codecov Report

Merging #599 into master will increase coverage by 0.04%.
The diff coverage is 87.50%.

@@            Coverage Diff             @@
##           master     #599      +/-   ##
==========================================
+ Coverage   84.88%   84.93%   +0.04%     
==========================================
  Files          52       52              
  Lines        2892     2934      +42     
  Branches      565      570       +5     
==========================================
+ Hits         2455     2492      +37     
- Misses        328      332       +4     
- Partials      109      110       +1     

Impacted Files	Coverage Δ
ocrd/ocrd/cli/zip.py	66.66% <0.00%> (-2.23%)	⬇️
ocrd_utils/ocrd_utils/__init__.py	100.00% <ø> (ø)
...d_validators/ocrd_validators/ocrd_zip_validator.py	100.00% <ø> (ø)
ocrd_utils/ocrd_utils/logging.py	85.13% <77.14%> (-3.55%)	⬇️
ocrd/ocrd/cli/workspace.py	76.55% <80.00%> (ø)
ocrd/ocrd/workspace.py	69.40% <88.88%> (+0.36%)	⬆️
ocrd/ocrd/cli/log.py	92.00% <100.00%> (+0.69%)	⬆️
ocrd/ocrd/cli/process.py	92.85% <100.00%> (+14.28%)	⬆️
ocrd/ocrd/cli/validate.py	100.00% <100.00%> (ø)
ocrd/ocrd/decorators/__init__.py	88.57% <100.00%> (ø)
... and 10 more

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[bertsky]

We are nearly there (if not already) IMO.

[bertsky]

Great work! (So OCR-D finally has a truly commendable and Pythonic logging system, both functionally and by implementation.)