Media loading flow changes (#483)

* Use an imageProvider directly from the view in the home screen

* Add support for media request coalescing

* Rename MediaProxy to MediaLoader

* Add new image loading mechanism to the room details screen avatar.

* Use the `SettingsScreen` prefix for all settings screen related components

* Add new image loading mechanism to the room header

* Add new image loading mechanism to the room member details screen

* Introduce a LoadableImage SwiftUI view that will automatically handle image loading

* Adopt the new LoadableImage where possible

* Fix LoadableImage not using/storing loaded images properly

* Simplify media loader enqueueing

* Made LodableImage load content after mediaSource updates. Adopt it on the home and settings screens

* Introduce a LoadableAvatarImage component and reuse it throughout the app

* Small logging tweaks, made some LoadableImage properties private

* Fix redacted skeletons avatar background color

* Fix placeholder avatars changing when backgrounding the app

* PR comments.

- Trim the @ sign off of mxid placeholders.
- Only expose AvatarSize on the avatar image, use CGSize elsewhere.

Co-authored-by: Doug <douglase@element.io>

ElementX/Sources/Screens/HomeScreen/HomeScreenModels.swift

@@ -34,7 +34,6 @@ enum HomeScreenViewUserMenuAction {
 }
 
 enum HomeScreenViewAction {
-    case loadRoomData(roomIdentifier: String)
     case selectRoom(roomIdentifier: String)
     case userMenu(action: HomeScreenViewUserMenuAction)
     case verifySession
@@ -59,7 +58,7 @@ enum HomeScreenRoomListMode: CustomStringConvertible {
 struct HomeScreenViewState: BindableState {
     var userID: String
     var userDisplayName: String?
-    var userAvatar: UIImage?
+    var userAvatarURL: URL?
     
     var showSessionVerificationBanner = false
     
@@ -96,7 +95,6 @@ struct HomeScreenViewStateBindings {
 
 struct HomeScreenRoom: Identifiable, Equatable {
     private static let placeholderLastMessage = AttributedString("Last message")
-    private static let placeholderAvatar = UIImage(systemName: "photo")
     
     /// The list item identifier can be a real room identifier, a custom one for invalidated entries
     /// or a completely unique one for empty items and skeletons
@@ -115,8 +113,6 @@ struct HomeScreenRoom: Identifiable, Equatable {
     
     var avatarURL: URL?
     
-    var avatar: UIImage?
-    
     var isPlaceholder = false
     
     static func placeholder() -> HomeScreenRoom {
@@ -126,7 +122,6 @@ struct HomeScreenRoom: Identifiable, Equatable {
                        hasUnreads: false,
                        timestamp: "Now",
                        lastMessage: Self.placeholderLastMessage,
-                       avatar: Self.placeholderAvatar,
                        isPlaceholder: true)
     }
 }