Move test data to Large File Storage

[NiklasPhabian]

We got away with the 100 MB limit so far, even though we had to cheat a little by granules that had a lot of masked values.

Good idea to address this before we fulfill #33

[NiklasPhabian]

Huh, that seems easier than I thought:
https://git-lfs.github.com/

[NiklasPhabian]

But I guess we started off with bad practice, so now we should migrate
https://github.com/git-lfs/git-lfs/blob/main/docs/man/git-lfs-migrate.adoc?utm_source=gitlfs_site&utm_medium=doc_man_migrate_link&utm_campaign=gitlfs

[NiklasPhabian]

git lfs install
git lfs track "*.nc"
git lfs track "*.hdf"
git lfs track "*.h5"
git lfs track "*.tiff"
git add .gitattributes

to migrate:

git lfs migrate import --fixup

https://git-lfs.github.com/
https://github.com/git-lfs/git-lfs/blob/main/docs/man/git-lfs-migrate.adoc?utm_source=gitlfs_site&utm_medium=doc_man_migrate_link&utm_campaign=gitlfs