Reland Move deprecated-ota code into a separate soong namespace

This reverts commit 20a288a5.

This offers better isolation, and allows two targets with the same name
to coexist(in different namespaces). During migration there will
be a short period of time where we have two copies of non-AB code.

Change-Id: I9fd38c3aa998ea096426b734b7728f67798d7afc
Test: th
Bug: 324360816