Divorce config loader from logging.yml

[antonymilne]

Note. Breaking, goes in 0.19.0.

Following #2281 we have decided that users will no longer be able to change logging configuration dependent on kedro run environment. This is a huge simplification and means that logging only gets configured once in the kedro process with LOGGING = _ProjectLogging().

There's a few things to be done here, but they all need to be done at the same time or it will be very confusing.

• Remove KedroSession._setup_logging and KedroSession._get_logging_config 🥳
• Remove everything to do with logging from all config loaders (e.g. in config_patterns and docstring examples)
• Double check you've removed everything that needs removing by searching logging throughout the whole codebase. Note that configure_logging must stay since it's needed by the parallel runner
• Update all starters to move conf/base/logging.yml to conf/logging.yml #2644
• Make sure you explain in the release notes migration guide that a custom logging file is now independent of kedro run environment and only used if KEDRO_LOGGING_CONFIG is set to point to it

[datajoely]

fantastic use of the verb

[noklam]

Closed by #2642