Fix avatar loading in multiple places and prefers name instead of

display name for avatar fallback.

This also fixes a bug where users didn't get their avatar loaded in the
room list.

Fix #209

imports/NeoChat/Component/Timeline/MessageDelegate.qml

@@ -51,7 +51,7 @@ RowLayout {
         Layout.alignment: Qt.AlignTop
 
         visible: showAuthor && Config.showAvatarInTimeline
-        name: author.displayName
+        name: author.name
         source: author.avatarMediaId ? ("image://mxc/" + author.avatarMediaId) : ""
         color: author.color