Batch calls to create app data for new users.

This significantly reduces IPC traffic between system server
and installd, resulting in a performance increase in
time to create a new user.

See associated installd API change:
https://android-review.googlesource.com/c/platform/frameworks/native/+/1285395

Bug: 153171028
Test: create guest user manually, trace with Perfetto.
Change-Id: I235730809cc0d9bf5dc94d1befdd3bafc43ae87c