Create root directory for supplemental data during user creation

In order to store supplemental data for apps, we want to create a root
directory at location `/data/misc_ce/<user-id>/supplmental` and
`/data/misc_de/<user-id>supplemental`. These directories will then host
supplemental data for each app based on package name, e.g,
`/data/misc_ce/0/supplemental/<app-name>`.

Since these are sub-directories of misc directory, vold should prepare
them for consistency.

Bug: 217543371
Test: atest SupplementalProcessStorageHostTest
Test: see ag/16681989
Ignore-AOSP-First: Feature is being developed in internal branch
Change-Id: I66ef7a7241c9f82cecedaeb6c9a91f127668300a