move from `edna-site` to `ci_datasets`

The goal of this PR is to open a bit more the dataset to users / developers. Instead of having a 'basic' folder accessible from edna-site that we must be aware of (as the contain) we can have a gitlab project, more findable and easier to visit.

All tomotools dataset will be stored in 'https://gitlab.esrf.fr/tomotools/ci_datasets'. Tomoscan will have a dedicated branch 'tomoscan'.

For now the REST API doesn't provide a way to download directly the requested file. So This is why I do the workaround with wget_file. I guess we can see with Cedric about it. Because the doc says that we should be able to reach the file directly (https://docs.gitlab.com/ee/topics/git/lfs/)