docs: update screen support doc to de-emphasize support for 1.5

this includes a variety of other revisions to reorganize some of the content in the main document
and also add separate documents for how to enable screen filtering and add screen support on 1.5

For more change history, also see Change-Id: Iadebc9ca3f2f5a0e7490466811f0d741fe2b2b8c

Change-Id: I78825116f5f7825da42120e840e5bc6d8d1e359c