Fixed Readme. Now it should reflect correct information.

Port C8 logging infrastructure to refactor.

Move implementations to .inl file in detail.

Delete commented out inline definition.

Switch to snake case and move default logger.

Remove explicit set_level methods.

Move default pattern into corsika::logging.

Remove superfluous comments and fix references.

Remove macros from .inl file.

Rename macros from C8LOG to CORSIKA_LOG

Remove double import of spdlog into corsika::logging