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