iOS: register lazy nativemodules on startup when Chrome is attached

Summary:
@public
This allows apps to specify custom lazy modules that they need to load during chrome debugging. This is because lazy modules won't be available on start up, hence these modules will be missing in JS land, causing problems.

Reviewed By: shergin

Differential Revision: D12899408

fbshipit-source-id: dca313648e994b22e3ee5afec856ef76470065f9