Use select:repo to speed up repository resolution
Created by: eseliger
This PR adopts select:repo to speed up initial resolution of matching repositories in batch changes, if the Sourcegraph instance supports it. To fetch file matches per repository, we each out to the server again to get the file results, per repo. This is significantly faster than waiting for all results for all repos to be retrieved.
Co-authored-by: Rijnard van Tonder [email protected]