Mount /dev/fuse on /mnt/user/<userid>/<volumeid>

Since system_server cannot mount devices by itself,
add a binder interface to vold that system_server
can call to initiate this mount when required.

BUG: 135341433
Test: manual
Test: atest --test-mapping packages/providers/MediaProvider
Test: ExternalStorageHostTest DownloadProviderTests

Change-Id: If4fd02a1f1a8d921a3f96783d8c73e085c5b7ca1
10 files changed