EXT-7972 FIXED (My Outfits: Add \"Add to current outfit\" menu item into gear menu)

- Added menu item 'Wear - Add to Current Outfit' (menu_outfit_gear.xml).
- Added menu item handler onAdd().

Reviewed by Mike Antipov at https://codereview.productengine.com/secondlife/r/657/

--HG--
branch : product-engine