Git LFS usage

[pomadchin]

We can use Git-LFS for test data files, that may improve repository cloning speed / test data versioning / etc.

[metasim]

As a part of this, it would be great to get rid of the .zip-ing of test data. Makes it a hassle to add new test images, and probably creates massive binary diffs every time you update it, but I'm not sure what the original rationale was.

[metasim]

Another idea is to have a separate repo and and artifact containing various test data. Not sure what the technical benefit, but it has aesthetic appeal to me for some reason.

[rossbernet]

related: geotrellis/geotrellis-chatta-demo#42

[pomadchin]

Do we still want to keep it open? GIT LFS is very limited in downloads in its free version.

[echeipesh]

We should close this. LocationTech is very reluctant in supporting git LFS for their repos and free tier is woefully insufficient.

I think we could use our own version of test utility which downloads test files from s3 and validate checksums such that we can avoid checking any more rasters in.