At Greg's request, hide Minerva on desktop behind a feature flag

See comment on CR from Greg on:
If3c896e56de68b50936de7942e376ceadebf096d

Change-Id: I2f8077df96e6c9edfd2ad16544cbffa4fcd61c7f
Merge "At Greg's request, hide Minerva on desktop behind a feature flag"