Migrate to React Native 0.66

[ximenabb]

Note from Gregor:

React Native 0.66 is out, so we can maybe migrate directly to that: . Related: When I had tried to upgrade to RN 0.65 before, nodejs-mobile was not building correctly. In my experiments with building Realm I figured out why.

Points: 13

[achou11]

I have some early work for upgrading to 0.65 (think I was blocked by some Flipper-related issue). Not sure if worth creating a remote branch for vis right now but in case we need somewhere to potentially start