advanced logging configuration

[ekneg54]

this PR aims to add more flexibility to the configuration of logpreps logging facility.
it implements the python dictConfig approach described here in the python logging documentation.

As we already use custom names for our loggers I decided to leave this contrary the best practice advice to use __name__ as the logger name. As a side effect we do not have a hierarchical order of our loggers anymore, but it gives us the flexibility to independently configure the log level of every logger in the configuration now. But I shortened the logger names in favor to get a better log output.

GOALS:

• configurable logging format
• add hostname to log entries
• configurable date format
• set level per log instance (root logger is DEBUG, but Pipeline 1 logs only ERROR)

TODO:

• add tests
• add documentation
• add changelog
• get rid of duplicate log messages

[dtrai2]

I had a look at it and only found some minor suggestions. The first thing I noticed is though, that when running logprep with python logprep/run_logprep.py run ./quickstart/exampledata/config/pipeline.yml I get a stacktrace telling me that the FileNotFoundError ... multiprocdir .... Logprep should rather tell me in a propper logmessage that the multiprocdir is missing, at least the stacktrace shouldn't be visible.