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/storage/postgres/storage.go

@@ -87,6 +87,10 @@ func Open(dataSourceName string, dbProperties sqlutil.DbProperties) (*Database,
 	if err != nil {
 		return nil, err
 	}
+	published, err := NewPostgresPublishedTable(db)
+	if err != nil {
+		return nil, err
+	}
 	d.Database = shared.Database{
 		DB:                  db,
 		EventTypesTable:     eventTypes,
@@ -101,6 +105,7 @@ func Open(dataSourceName string, dbProperties sqlutil.DbProperties) (*Database,
 		RoomAliasesTable:    roomAliases,
 		InvitesTable:        invites,
 		MembershipTable:     membership,
+		PublishedTable:      published,
 	}
 	return &d, nil
 }