Show or create direct message room (#716)

* add start chat flow with UI

* add feature flag for start chat

* add changelog

* fix naming and tests

* fix empty display name in user cell

* Update ElementX/Sources/Application/AppSettings.swift

Co-authored-by: Alfonso Grillo <alfogrillo@element.io>

* add screenshots from UI test

* fix swiftFormat and add identifiers

* fix warnings

* add the create or open already existing direct room feature

* add changelog

* add UserProfile object, add loading indicator in start chat flow

* fix test

* add new section for user profile in start chat

* fix duplicates input on search bar

* Update ElementX/Sources/Services/Client/ClientProxy.swift

Co-authored-by: Alfonso Grillo <alfogrillo@element.io>

* Update ElementX/Sources/Services/Client/ClientProxy.swift

Co-authored-by: Alfonso Grillo <alfogrillo@element.io>

---------

Co-authored-by: Alfonso Grillo <alfogrillo@element.io>

ElementX/Sources/Other/AvatarSize.swift

@@ -46,6 +46,7 @@ enum UserAvatarSizeOnScreen {
     case home
     case settings
     case roomDetails
+    case startChat
 
     var value: CGFloat {
         switch self {
@@ -57,6 +58,8 @@ enum UserAvatarSizeOnScreen {
             return 60
         case .roomDetails:
             return 44
+        case .startChat:
+            return 36
         }
     }
 }