CMFileManager: Updated menu strings to reduce confusion regarding copy & move

Changed menu strings should help users understand that files will be moved
to current folder.

msgs_operation_not_allowed_in_current_directory change should make clear
that it is "move a to a" issue rather than missing root access or insufficient
privileges.

Change-Id: I007bbec91c89f5e0eb4caefc721cfb6facdd0a0f