Refactor the JoinRoom screen to take advantage of newer APIs and support more joinRule/membership combinations (i.e. invite required, restricted, banned) (#3685)

- expose the full RoomPreview and RoomMembershipDetails through their own proxies
- implement standard mocks for all the different combinations
- converge on a single room info provider
- rebuild all the previews
- prioritise the preview data over the room one.

ElementX/Sources/Services/Room/RoomPreview/RoomPreviewProxy.swift

@@ -0,0 +1,35 @@
+//
+// Copyright 2024 New Vector Ltd.
+//
+// SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+// Please see LICENSE files in the repository root for full details.
+//
+
+import MatrixRustSDK
+
+final class RoomPreviewProxy: RoomPreviewProxyProtocol {
+    private let roomPreview: RoomPreview
+    
+    let info: RoomPreviewInfoProxy
+    
+    init(roomPreview: RoomPreview) throws {
+        self.roomPreview = roomPreview
+        info = try .init(roomPreviewInfo: roomPreview.info())
+    }
+    
+    var ownMembershipDetails: RoomMembershipDetailsProxyProtocol? {
+        get async {
+            guard let details = await roomPreview.ownMembershipDetails() else {
+                return nil
+            }
+            
+            var senderRoomMember: RoomMemberProxy?
+            if let member = details.senderRoomMember {
+                senderRoomMember = .init(member: member)
+            }
+            
+            return RoomMembershipDetailsProxy(ownRoomMember: RoomMemberProxy(member: details.ownRoomMember),
+                                              senderRoomMember: senderRoomMember)
+        }
+    }
+}