security: Log AccessGranted events when repo accessed directly
Created by: ryanslade
Log AccessGranted event when private repo accessed
I added some instrumentation to see how often this happens, which right now is not a lot: https://sourcegraph.com/-/debug/grafana/explore?orgId=1&left=%5B%22now-1h%22,%22now%22,%22Prometheus%22,%7B%22exemplar%22:true,%22expr%22:%22max(src_access_granted_private_repo)%22,%22requestId%22:%22Q-e60cde3b-6771-4b1e-b23c-196cc38600a3-0A%22%7D%5D
I've also added counter for where I plan to log events when listing repos