[FR] Trigger sync for all repos via the settings/connections screen

With large number of repo's in sourcebot, we regularly run into issues where a lot of repos fail the sync. Usually, rerunning the sync succeeds so its not a big issue. Occasionally there are 100+ repos that have their sync failed. It would be convenient to be able to trigger sync for all repos (or only for failing repos) via a button in the `/settings/connections/<repo number>` screen