ocs share api: add "received_from" and "received_from_displayname" field

add "received_from" and "received_from_displayname" field in case of a reshared file to the output.

This fields are added if the user asks for all shares from a given file ```ocs/v1.php/apps/files_sharing/api/v1/shares?path=folder&subfiles=true```, if the user asks for a specific share ```ocs/v1.php/apps/files_sharing/api/v1/shares/shareID``` or for the status of a specific file ```ocs/v1.php/apps/files_sharing/api/v1/shares?path=file```.

cc @DeepDiver1975