[WIP] Tests: add LFS-related tests

[pameladelgado]

This PR adds new GitLFSSpec to test an LFS connection is working properly also involving environments.

What has been done: importing a dataset from the UI, which seems to be working properly.

What is incomplete: start an environment with the Auto-fetch checkbox enabled an verify that the imported dataset has been pulled from LFS. In particular, verify that launchEnvironmentAutoFetch method is working properly and finish implementing verify zipped dataset method. The code can also be enhanced by not hard-coding values that are used to refer to the dataset (see TODOs).

Deploying just to test CI

/deploy

[RenkuBot]

You can access the deployment of this PR at https://ci-renku-1989.dev.renku.ch

[rokroskar]

Closing due to inactivity