Prune frontend state tree

[mertkahyaoglu]

Content of the PR;

• After Expose documents on collection index #211, collections/collection/documents/ endpoint is deprecated and documents key is moved to collections/collection/path endpoint. With this API change, the front end is fetching a collection and its documents with a single call. This allows us to store the information from that call in a single object rather than storing collections and documents of currently visited collection separately.

Before;

After currentDocuments removed;

• Secondly, the front end now follows another method of deleting files. Formerly, once a file was deleted, it was filtered out from the list state until another request was made for that list. Now once it is deleted, a new list request is made rather than relying on the state. This ensures that the front end state is the same as the back end's.