The new actions framework has a lot more flexibility and consistency

than the old one. This change ports over our existing review request

actions and extension hooks to use it. In addition, several things which

worked like actions (like the star and archive/mute menu) but were

implemented outside of the framework have been rewritten to be actions

instead.
This also reimplements the client-side styling and logic for menus and

the mobile menu, using the new CSS component style and building on

RB.MenuView for the drop-downs. This gives us more consistent style

rules as well as support for keyboard and screen-reader accessibility.

Tested review request actions in several scenarios, including when

  logged out and in mobile mode.
Ran unit tests.