Move even more vold commands over to Binder.

This moves fstrim, obb and appfuse commands over to the new Binder
interface.  This change also separates creating/destroying and
mounting/unmounting of OBB volumes, which means they finally flow
nicely into the modern VolumeInfo/VolumeBase design.

Test: cts-tradefed run commandAndExit cts-dev -m CtsOsTestCases -t android.os.storage.cts.StorageManagerTest
Bug: 13758960
Change-Id: I4de45889828a9ab9858cc7c4f094a90eaff10f96