Replace publicroomsapi with a combination of clientapi/roomserver/currentstateserver (#1174)

* Use content_value instead of membership

* Fix build

* Replace publicroomsapi with a combination of clientapi/roomserver/currentstateserver

- All public rooms paths are now handled by clientapi
- Requests to (un)publish rooms are sent to the roomserver via `PerformPublish`
  which are stored in a new `published_table.go`
- Requests for public rooms are handled in clientapi by:
    * Fetch all room IDs which are published using `QueryPublishedRooms` on the roomserver.
    * Apply pagination parameters to the slice.
    * Do a `QueryBulkStateContent` request to the currentstateserver to pull out
      required state event *content* (not entire events).
    * Aggregate and return the chunk.

Mostly but not fully implemented (DB queries on currentstateserver are missing)

* Fix pq query

* Make postgres work

* Make sqlite work

* Fix tests

* Unbreak pagination tests

* Linting

roomserver/api/api.go

@@ -36,6 +36,18 @@ type RoomserverInternalAPI interface {
 		res *PerformLeaveResponse,
 	) error
 
+	PerformPublish(
+		ctx context.Context,
+		req *PerformPublishRequest,
+		res *PerformPublishResponse,
+	)
+
+	QueryPublishedRooms(
+		ctx context.Context,
+		req *QueryPublishedRoomsRequest,
+		res *QueryPublishedRoomsResponse,
+	) error
+
 	// Query the latest events and state for a room from the room server.
 	QueryLatestEventsAndState(
 		ctx context.Context,