Various performance tweaks (#474)

* Store and reuse room list placeholder avatars and last messages

* Cache and reuse HomeScreenRooms

* Reduce RoomSummaryProvider diff collection time

* Promote more logs to info

* Slighty tweak RustTracing to make it easier to configure

* Move TimelineProvider and RoomTimelineController item processing to background queues

* Prevent the timeline from stopping an ogoing decelerating scroll when starting backpaginating

ElementX/Sources/Services/Room/RoomSummary/RoomSummaryProvider.swift

@@ -56,7 +56,7 @@ class RoomSummaryProvider: RoomSummaryProviderProtocol {
             .store(in: &cancellables)
         
         slidingSyncViewProxy.diffPublisher
-            .collect(.byTime(serialDispatchQueue, 0.1))
+            .collect(.byTime(serialDispatchQueue, 0.025))
             .sink { [weak self] in self?.updateRoomsWithDiffs($0) }
             .store(in: &cancellables)
     }
@@ -80,7 +80,7 @@ class RoomSummaryProvider: RoomSummaryProviderProtocol {
             return
         }
         
-        MXLog.verbose("Updating \(identifiers.count) rooms")
+        MXLog.info("Updating \(identifiers.count) rooms")
         
         guard statePublisher.value == .live else {
             MXLog.warning("Sliding sync not live yet, ignoring update.")
@@ -117,7 +117,7 @@ class RoomSummaryProvider: RoomSummaryProviderProtocol {
     }
     
     fileprivate func updateRoomsWithDiffs(_ diffs: [SlidingSyncViewRoomsListDiff]) {
-        MXLog.verbose("Received \(diffs.count) diffs")
+        MXLog.info("Received \(diffs.count) diffs")
         
         rooms = diffs
             .reduce(rooms) { currentItems, diff in
@@ -136,7 +136,7 @@ class RoomSummaryProvider: RoomSummaryProviderProtocol {
                 return updatedItems
             }
         
-        MXLog.verbose("Finished applying \(diffs.count) diffs")
+        MXLog.info("Finished applying \(diffs.count) diffs")
     }
         
     private func buildRoomSummaryForIdentifier(_ identifier: String, invalidated: Bool) -> RoomSummary {