Add gencast support

[Sukh-P]

Pull Request

Description

These changes are to have ruvnl models running from this app, including running a GenCast based model, so adding extra logic to pull the required gencast data to this app, changes include:

• Adding 2 new models for ruvnl
• Adding logic to pull required gencast data from GCS buckets at runtime and process them into required formats
• Adding testing arounds this changes
• Tweaking tests to work with new models as well as old ones
• Adding logic around if a pv or wind site to only set night zeros for PV sites

Still need to make infrastructure changes for this to run properly