Support for renaming documents.

DocumentsProviders can mark documents as supporting rename, and they
have the opportunity to change the DOCUMENT_ID as a side effect of
the rename.  This supports providers that embed the display name
into DOCUMENT_ID.  Issues a URI permission grant to the new document,
if any.

Adds renaming support to platform ExternalStorageProvider.  Also
adds directory deletion support.

Bug: 12350110
Change-Id: Ica4b1ae6769ee994f70f6b6b2402213eebd064e0