Supply Target Folder when adding Remote Dataset

[fm3]

Starting in #7176 (still WIP as of this writing) the backend supports a folderId field for the add route called by the frontend in storeRemoteDataset. The frontend should use that (and show a folder selection menu just like in the upload view).

This way the normal folder rights management is also respected when storing remote datasets. Otherwise, the user can only add remote datasets when having write access to the root folder

Related: #7199

[fm3]

Turns out the front-end calls updatePartial, setting the folder id, after hitting the add button. That should be removed in favor of passing the folderId to storeRemoteDataset (as introduced in #7176 in the backend)

[fm3]

I extracted the relevant changes from #7176 to the new smaller PR #7221 to avoid this being blocked for so long. Could you add the front-end changes there?

[philippotto]

Could you add the front-end changes there?

Done :)