Diffable fade animations (#1343)

* animate only 2 seconds after the appearence

* scrolling is stable

* code improvement

* comment and removing code that is not necessary anymore

* feature flag

* comment

* better code

* the day divider ID is the timestamp itself as ISO

* Apply suggestions from code review

Co-authored-by: Alfonso Grillo <alfogrillo@gmail.com>

* format fix

---------

Co-authored-by: Alfonso Grillo <alfogrillo@gmail.com>

ElementX/Sources/Screens/Settings/DeveloperOptionsScreen/DeveloperOptionsScreenModels.swift

@@ -32,6 +32,7 @@ struct DeveloperOptionsScreenViewStateBindings {
     var locationEventsEnabled: Bool
     var shareLocationEnabled: Bool
     var notificationSettingsEnabled: Bool
+    var timelineDiffableAnimationsEnabled: Bool
 }
 
 enum DeveloperOptionsScreenViewAction {
@@ -42,5 +43,6 @@ enum DeveloperOptionsScreenViewAction {
     case changedLocationEventsEnabled
     case changedShareLocationEnabled
     case changedNotificationSettingsEnabled
+    case changedTimelineDiffableAnimationsEnabled
     case clearCache
 }