Add Fischer-Tropsch part load

[energyLS]

Changes proposed in this Pull Request

Add part load option for Fischer-Tropsch. Previously, there was no part load constraint for Fischer-Tropsch, which is introduced here and adjustable in the config. The implementation is similar to:

https://github.com/PyPSA/pypsa-eur/blob/f35ecbe4a01f220210c3a295ca93d805f5633824/scripts/prepare_sector_network.py#L2722-L2724

Checklist

• [x] I tested my contribution locally and it seems to work fine.
• [x] Code and workflow changes are sufficiently documented.
• [x] Newly introduced dependencies are added to envs/environment.yaml and envs/environment.docs.yaml.
• [x] Changes in configuration options are added in all of config.default.yaml, config.tutorial.yaml, and test/config.test1.yaml.
• [x] 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, including reference to the requested PR.

[energyLS]

Mac CI successful, please review and merge @hazemakhalek :)