Composite: Allow forcing hardware composition

While it's handy to have a fallback system in place when hardware composition is not available, it makes it easy for us to succeed at showing something but offer a sub-par experience.

This option is designed for systems where this is not an option, it allows us to make sure we are running in ideal conditions or otherwise failing and addressing whatever the problem is in the right place in the stack.

Signed-off-by: Victoria Fischer victoria.fischer@mbition.io