Trigger OAuth flow for creating personal code host connection through GitHub App
Created by: pjlast
This PR implements CLOUD-205.
If a user adds a personal codehost connection while belonging to an organization that has the GitHub App feature flag enabled, GitHub App will be used to trigger the OAuth flow instead.
https://user-images.githubusercontent.com/6427795/152993745-3d91db56-5095-4bde-82e0-9663826f8e58.mp4
There may be some follow-up work required for this ticket, such as making sure that the backend is processing the GitHub App Oauth callback correctly, since currently, after adding the code host connecting, Sourcegraph asks to update the GitHub connection.
EDIT: Updated video: