Consistent shape for data sources

[nbren12]

Earth-2 MIP Pull Request

Description

Scoring with hdf5 files fails. This was caused by inconsistent handling of the batch dimension.

Previously data sources inserted this themselves so data_source[time].shape is (1, channel, lat, lon), but this is confusing and not how the hdf5.DataSource works. DataSources should just get (channel, lat, lon). I documented this in the base.DataSource and modified our data sources accordingly. I also removed some duplicate test files.

Checklist

• [x] I am familiar with the Contributing Guidelines.
• [x] New or existing tests cover these changes.
• [x] The documentation is up to date with these changes.
• [x] The CHANGELOG.md is up to date with these changes.
• [x] An issue is linked to this pull request.

Dependencies

[nbren12]

/blossom-ci

[nbren12]

/blossom-ci