add feature: aggregate carrier exclusion

[p-glaum]

Changes proposed in this Pull Request

This is a feature which allows you to exclude carriers from the aggregation during the clustering or simplify network. With the default setting, nothing compared to the current master changes.

Checklist

• I tested my contribution locally and it seems to work fine.
• Code and workflow changes are sufficiently documented.
• Newly introduced dependencies are added to envs/environment.yaml and envs/environment.docs.yaml.
• Changes in configuration options are added in all of config.default.yaml, config.tutorial.yaml, and test/config.test1.yaml.
• Changes in configuration options are also documented in doc/configtables/*.csv and line references are adjusted in doc/configuration.rst and doc/tutorial.rst.
• A note for the release notes doc/release_notes.rst is amended in the format of previous release notes.

[fneum]

Nice feature, especially for market modelling with PyPSA-Eur. Couple of comments below:

[FabianHofmann]

Looks good!