Summary:
Convert section plugin to Sandy API.
TODO
- Fix layout issues
- scrollbar occurs in small component (bottom layout)
- scrollbar in wrong place (top layout)
- text shrunk in bottom part of tree component
- (?) move away from d3
- better typing for payload
- move components to functional one
- unit test
Reviewed By: mweststrate
Differential Revision: D22385993
fbshipit-source-id: 862d4b775caf2d9a7bcb37446299251965a5d6db
