Make contacts photo pickers compatible with new documents UI

The old contacts photo picker code was using unguaranteed behavior
(that Intent.GET_CONTENT would support MediaStore.EXTRA_OUTPUT) and this
caused it to not work anymore with the new document picker.

This CL changes all usages of files to instead use URIs.

Also, a FileProvider has been added to Contacts, to allow us to pass in
URI pointing to our private cache in intent.setClipData with
Intent.FLAG_GRANT_WRITE_URI_PERMISSION and Intent.FLAG_GRANT_READ_URI_PERMISSION
so we no longer have to reply on the MediaStore.EXTRA_OUTPUT being parsed
and supported. The use of the FileProvider also prevents unauthorized access
to temporary files during the caching process.

Bug: 10745342

Change-Id: Iaee3d7d112dd124a2f5596c4b9704ea75d3b3419
Merge branch 'cm-10.2' into martincz