we no longer need to handle the Shared folder different from any other folder
fix share api tests
fix target generation for group shares
fix encryption tests after the removal of the shared folder
fix updating of shared files
fix deleting of shared files
make sure that path is not 'false'
allow user to delete shared files/folders
also fetch the etag from file cache
external storages: allow to mount a folder called "Shared", it is no longer a reserved name