Feat: Add France solar generation data pipeline

[Her0n24]

Pull Request

Description

This PR follows #121, adds data download and processing pipelines for France to prepare PVNet training for France.

Changes:
Completed step 1-4

• Script for downloading solar PV generation and capacity data for the 12 admin metropolitan (mainland) France regions
• Metadata of the 12 admin regions
• Script for checking and processing the Réseau de Transport d'Électricité (RTE) éCO2mix datasets into the required .zarr format

I will update documentation, upload the .zarr and raw data before moving on to step 5.

How Has This Been Tested?

Ran inspect_france_training_pipeline.py on local machine:

• Dataset attributes complete, 87696 of monotonically increasing time steps between 2019-12-31T23:00:00 to 2024-12-31T22:30:00

• NaN, min-max values verification (NaN accounts 0.01% of total)

• One month of solar generation patterns with all 12 regions to very diurnal cycles and orders of magnitude

• Yes

If your changes affect data processing, have you plotted any changes? i.e. have you done a quick sanity check?

• Yes

Checklist:

• My code follows OCF's coding style guidelines
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• I have checked my code and corrected any misspellings