Add support for sending media within threads.

This patch add the `threadRootEventID` as a parameter to media sending functions and forwards the timeline thread root between various application states to the place where its needed.
The 2 missing items are Locations and Polls which currently don't have any support on the Rust side for being sent within threads. That will come in a separate PR.

ElementX/Sources/Screens/RoomScreen/RoomScreenCoordinator.swift

@@ -98,6 +98,7 @@ final class RoomScreenCoordinator: CoordinatorProtocol {
                                                         parserStyle: .elementX)
         let composerViewModel = ComposerToolbarViewModel(initialText: parameters.sharedText,
                                                          roomProxy: parameters.roomProxy,
+                                                         isInThread: false,
                                                          wysiwygViewModel: wysiwygViewModel,
                                                          completionSuggestionService: parameters.completionSuggestionService,
                                                          mediaProvider: parameters.mediaProvider,