Summary:
A registry for components. The registry allows to refer to component view instance by react tag.
It also has recycle-pool-like interface (and eventually the pool will be implemented).
Reviewed By: mdvacca
Differential Revision: D7507519
fbshipit-source-id: ed74203fb4d0694490b0dc23aae0aa067b3fc55b
Valentin Shergin