BG-3338: Handle BitGo Express routes on the server
BG-3338: Handle BitGo Express routes on the server

Summary: Left a comment in src/clientRoutes.js describing where to add BitGo Express routes on the server.

Reviewers: bigly, thomas, arik

Reviewed By: thomas, arik

Subscribers: ben

Differential Revision: https://phabricator.bitgo.com/D7976

BitGo/BitGoJS,BitGo/BitGoJS,BitGo/BitGoJS,BitGo/BitGoJS