repo-updater: Only exclude cloud_default external services from sync and index
Created by: ryanslade
On cloud we will now sync all external services in the background unless they are flagged as cloud_default.
In practice this means that we won't sync our large GitHub and GitLab public external services that own all of our "on demand sync" repos. But, we will now start to sync all other external services whether they are added by users or site admins.
Additionally, any repos synced by non cloud_default external services will also be indexed.
After this change the following external services will begin to sync in the background and have their repos indexed:
Android, 1 repo: https://sourcegraph.com/site-admin/external-services/RXh0ZXJuYWxTZXJ2aWNlOjEx OCF (Berkeley), 93 repos: https://sourcegraph.com/site-admin/external-services/RXh0ZXJuYWxTZXJ2aWNlOjM3 SrcHut, 2 repos: https://sourcegraph.com/site-admin/external-services/RXh0ZXJuYWxTZXJ2aWNlOjU= Chromium, 1 repo: https://sourcegraph.com/site-admin/external-services/RXh0ZXJuYWxTZXJ2aWNlOjE2
Closes: https://github.com/sourcegraph/sourcegraph/issues/17472