Move API-related annotations

Before we start scattering references to the API annotations
in lots of place they should be moved to a nicer location / given
nicer names. The annotations will be easier to manipulate in source
if they are fully qualified so this change also removes imports / fully
qualifies all usages.

Bug: 113148576
Test: build
Change-Id: Iee7f7a02405f9240fda4f3faacb1627c8bb3f311
9 files changed