codeintel: Consolidate janitors

Created by: efritz

This PR moves the precise-code-intel-api-server janitor functionality into the bundle-manager janitor. This is a pre-step to merging the api-server and the frontend (as the only meaningful thing left in the api-server is now the API/server layer).

This also has the effect of allowing the bundle-manager to talk directly to Postgres, but only inside of the janitor process. This removes a bunch of network hops between the api-server and the bundle-manager (from both directions) in order to ensure that the disk and database have the same consistent view.