Summary:
This diff moves the preferences interface to a sheet in the main window, with the following benefits:
- We can put any sort of React control in it (no ReactRemote)
- It's not strange for the interface to scroll
- Since it can scroll, it's safe to auto-generate preferences for plugins based on their package config schema.
The general tab is now mostly based on the config schema, with the exception of the "Workspace" and "Layout" bits.
The other tabs are still manual, and should be polished more.
Test Plan: No new tests
Reviewers: evan
Reviewed By: evan
Differential Revision: https://phab.nylas.com/D2278
