Revert "Split Stk into a client apk and a lib."

This reverts commit f17bb5778ab1678601cfb171eec7213de63bbefc.

Reason for revert: b/148821604

Merged-in: I9f5682f99c73c447a5af8d29ed662f1bd68a0bf6
Change-Id: Idac4e818cbe54b417932603585540f1fd63c503e
14 files changed