Add Contributor Only Pet Choice

This PR https://github.com/HabitRPG/habitrpg-shared/pull/33 should completed before this one.
Update pets.jade
Rare Pets Layout

Shows rare pets header always.

Shows golden missing rare pet graphic if Hydra not obtained with link to how to obtain it.
Merge remote-tracking branch 'Shaners/patch-3' into contrib

Conflicts:
	views/options/pets.jade