Improve accuracy of Generation Units

[BenjaminWatts]

Generation plant locations are defined in [state/gb/fixtures/generators/unit-groups.tsx](https://github.com/kilowatts-io/kilowatts-grid/blob/production/backend/lambda/gb_snapshot/bm/generation.py)

While the locations and bmUnits are accurate for the majority of units - there are some, particularly smaller ones (like batteries) where the locations were done at haste - or changes have occured.

Any help with keeping this up to date, and correcting locations would be be much appreciated. No in-depth understanding of the broader code is required.