Add GTN-P reference layers: CALM and TSP sites

[trey-stafford]

Description

These would be nice reference layers, but the GTN-P data policy states:

Downloaded data cannot be redistributed to others and must not be redistributed via other websites, databases r any other storage system to prevent circulation of different versions of the datasets.

An understandable concern, but since these are primarily refernece layres that point to the actual timeseries data (except for the CALM layer, see below), maybe these would be allowed. We could reach out to the maintainers of the GTN-P database to get their approval if we feel strongly about it.

The CALM layer is the only one that seems to contain actual data (1990-2017). This layer seems to mirror the data on the CALM site, but is older.

Checklist

If an item on this list is done or not needed, simply check it with [x].

• [ ] Config lockfile updated (inv config.export > qgreenland/config/cfg-lock.json)
• [ ] Version bumped if needed (bumpversion (major|minor|patch|prerelease|build)
• [ ] CHANGELOG.md updated
• [ ] Documentation updated if needed
• [ ] New unit tests if needed

[trey-stafford]

Declining this PR for now. If we decide to pursue getting permission for one or both of the ref layers added in this PR, we can re-open.