Render state items in the timeline and as the last message on the home screen. (#473)

* State events in the timeline WIP
* Implement membership change strings.
* Add other state event types and use in RoomSummaryProvider.

Co-authored-by: Stefan Ceriu <stefanc@matrix.org>

ElementX/Sources/Screens/RoomScreen/View/Timeline/StateRoomTimelineView.swift

@@ -0,0 +1,43 @@
+//
+// Copyright 2023 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import SwiftUI
+
+struct StateRoomTimelineView: View {
+    let timelineItem: StateRoomTimelineItem
+    
+    var body: some View {
+        Text(timelineItem.text)
+            .font(.element.caption1Bold)
+            .multilineTextAlignment(.center)
+            .foregroundColor(.element.secondaryContent)
+            .frame(maxWidth: .infinity, alignment: .center)
+            .padding(.horizontal, 16)
+            .padding(.vertical, 4)
+    }
+}
+
+struct StateRoomTimelineView_Previews: PreviewProvider {
+    static var previews: some View {
+        body
+        body.timelineStyle(.plain)
+    }
+    
+    static var body: some View {
+        let item = StateRoomTimelineItem(id: UUID().uuidString, text: "Alice joined", timestamp: "Now", groupState: .beginning, isOutgoing: false, isEditable: false, sender: .init(id: ""))
+        return StateRoomTimelineView(timelineItem: item)
+    }
+}