Add support for manifest based opt-in for game modes

Also add support for games to opt-out of specific
interventions via manifest.

Manifest metadata tag name attributes need to be one of:
"com.android.graphics.intervention.wm.allowDownscale"
"com.android.app.gamemode.performance.enabled"
"com.android.app.gamemode.battery.enabled"
and the value attribute must be "true"

Bug: b/184849707, b/186582669

Test: atest com.android.server.app.GameManagerServiceTests
Change-Id: I0d09c1e1fb9ac704bb92cf65000d6f78a67e42fd