Introduce "unlocking" vs "unlocked" nuance.

There is a narrow window of time during user unlock where we're
reconciling user storage and dispatching the "unlock" status to
various internal system services.  While in this "unlocking" state,
apps need to be told that the user still isn't actually "unlocked"
so they don't try making calls to AccountManager, etc.

The majority of internal services are interested in merging together
both the "unlocking" and "unlocked" state, so update them.

Clarify naming in AccountManagerService to make it clear that a local
list is being used, which mirrors the naming in MountService.

To match UX/PM requested behavior, move PRE_BOOT_COMPLETED dispatch
after the user is unlocked, but block BOOT_COMPLETED dispatch until
after all PRE_BOOT receivers are finished to avoid ANRs.

Bug: 28040947, 28164677
Change-Id: I57af2351633d9159f4483f19657ce0b62118d1ce