config: add separate cache for stdout/remote sinks

[VJanKraemer]

Subject

The current implementation had a bug, which prohibited a user from adding a remote and a stdout sink at the same time to a participant. The bug was fixed by adding separate caches for each logging sink type.

Instructions for review / testing

Build the CanDemo. Run the CanDemo with the folloging logging Config:

Logging: Sinks:

• Type: Remote Level: Trace LogName: CanWriterLog
• Type: Stdout Level: Trace LogName: CanWriterLog

Developer checklist (address before review)

• [ ] Changelog.md updated
• [ ] Prepared update for depending repositories
• [ ] Documentation updated (public API changes only)
• [ ] API docstrings updated (public API changes only)
• [ ] Rebase → commit history clean
• [ ] Squash and merge → proper PR title

[VJanKraemer]

The changes look good to me! 👍 Could you add a simple unit-test to make sure duplicates result in an error during merges and merged sinks are included in the final config?

Sure thing, this is a good idea 👍