Don't use the FDE flow to support metadata encryption; just provide a
vold service which directly mounts the volume and use that.
Bug: 63927601
Test: Boot Taimen to SUW with and without metadata encryption.
Change-Id: Ifc6a012c02c0ea66893020ed1d0da4cba6914aed
Support encrypting metadata in /userdata using the dm-default-key
driver with a key in the /metadata partition.
Bug: 29189559
Test: Angler & Marlin build and boot
Change-Id: I716b117508d4bb4f6a4039293acb848cbc60f67b