Improve agg_p_nom_limits configuration

[tgi-climact]

Changes proposed in this Pull Request

Improved the behaviour of agg_p_nom_limits:

• Moved the associated configuration to solving. This allows Snakemake to correctly decide which rules to run when the configuration changes.

• Added the ability to enable aggregation of all offwind types (offwind-ac and offwind-dc) when writing the constraint.

• Added the possibility to take existing capacities into account when writing the constraint.

• Added the possibility to have a different file for each planning horizon.

Checklist

• [x] I tested my contribution locally and it seems to work fine.
• [x] Code and workflow changes are sufficiently documented.
• [ ] Changed dependencies are added to envs/environment.yaml.
• [x] Changes in configuration options are added in all of config.default.yaml.
• [x] Changes in configuration options are also documented in doc/configtables/*.csv.
• [x] A release note doc/release_notes.rst is added.

[tgi-climact]

@FabianHofmann Would it be useful to add some code to extend this feature to links ? e.g. write constraint into agg_p_nom_minmax.csvfor nuclear

[fneum]

@tgi-climact all looks good!

Yes, I think it makes sense to extend this feature to links. I'll merge this PR first, and then we can extend.

[tgi-climact]

@tgi-climact all looks good!

Yes, I think it makes sense to extend this feature to links. I'll merge this PR first, and then we can extend.

Great, I will propose a new PR when I have some time.