[2506][DRAFT] Toy datasets for anemoi

[tjhunter]

Description

Not meant to be merged.

• adding toy datasests and instructions to run WG in 30 minutes from scratch. Complementary to [2506][DRAFT] First step of publically runnable version #2514 (the main branch)
• attempt to have a CPU-only version (not successful, likely too many changes)

Instructions:
https://gitlab.jsc.fz-juelich.de/hedgedoc/s/5ykm9w_kV

Issue Number

Is this PR a draft? Mark it as draft.

Checklist before asking for review

• I have performed a self-review of my code
• My changes comply with basic sanity checks:
  • I have fixed formatting issues with ./scripts/actions.sh lint
  • I have run unit tests with ./scripts/actions.sh unit-test
  • I have documented my code and I have updated the docstrings.
  • I have added unit tests, if relevant
• I have tried my changes with data and code:
  • I have run the integration tests with ./scripts/actions.sh integration-test
  • (bigger changes) I have run a full training and I have written in the comment the run_id(s): launch-slurm.py --time 60
  • (bigger changes and experiments) I have shared a hegdedoc in the github issue with all the configurations and runs for this experiments
• I have informed and aligned with people impacted by my change:
  • for config changes: the MatterMost channels and/or a design doc
  • for changes of dependencies: the MatterMost software development channel

[clessig]

On having a smaller dataset, it's easy to build 1 year of the standard O96 ERA5: https://github.com/ecmwf/anemoi-datasets-configs. This would be useful so that people can run inference easily.