Use actual file path on rename/delete

When renaming or deleting a file that is in a subdirectory, performing
the action from the sharing overview or another file list view, the
actual directory of the file must be used instead of the current
directory.
Add server<->server sharing backend
add remote/add external shares to manager
Add coments to database and dont use sql keywords as table names
Add interface for accpeting external shares
Add interface for adding a public share to a different ownCloud instance
Fix exposing single files over webdav
Support path lengths up to 4000 chars
Fix removing remote shares
Dont return false for internalPath
Improve detection of whether we're in the files app
Scan the entire remote share at once by requesting the full file tree from the remote server
make sure to enable incognito mode when mounting a public link and update init status of the encryption app
exclude mounted server-to-server shares from encryption
Update for changes in master
Generate a unique name
Save mountpoints relative to the user
Fix prompting for password
if file doesn't exist, check parent folder
Fix checking for external share in encryption