Support default, pattern, pin and password encryption types

Java plumbing to expose methods to get/set encryption type in
IMountService, and hooking up of those methods to the Settings app
so the type is set correctly.

Needs matching vold changes from
 https://googleplex-android-review.googlesource.com/#/c/412649/

Bug: 8769627
Change-Id: I70c0ed72d11f5ab6f0958a7f9c101b6822b13baa