Add dependency management, AvatarViewModel and placeholder rendering now in AvatarImage.

Riot/Modules/Common/Avatar/ViewModel/AvatarService.swift

@@ -50,6 +50,7 @@ class AvatarService: AvatarServiceType {
      If possible to retrieve the actual image it will from network or cache, otherwise it will error.
      
     - Parameter mxContentUri: matrix uri of the avatar to fetch
+    - Parameter avatarSize: The size of avatar to retrieve as defined in the DesignKit spec.
     - Returns: A Future of UIImage that returns an error if it fails to fetch the image
      */
     @available(iOS 14.0, *)

Riot/Modules/Common/Avatar/ViewModel/AvatarViewModel.swift

@@ -18,10 +18,12 @@ import Foundation
 import Combine
 import DesignKit
 
+/**
+Simple ViewModel that supports loading an avatar image of a particular size
+ as specified in DesignKit and delivering the UIImage to the UI if possible.
+ */
 @available(iOS 14.0, *)
-class AvatarViewModel: ObservableObject, Injectable {
-    
-    var dependencies: DependencyContainer!
+class AvatarViewModel: InjectableObject, ObservableObject {
     
     @Inject var avatarService: AvatarServiceType