Add the new bloom style under a feature flag. (#4033)

* Refactor the bloom into a modifier.

It currently depends on the home screen context but that will be removed in the future.

* Add an initial implementation of the new bloom using an image on the navigation item's appearance.

* Add a feature flag to control the new bloom.

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

@@ -47,6 +47,7 @@ protocol DeveloperOptionsProtocol: AnyObject {
     var reportRoomEnabled: Bool { get set }
     var reportInviteEnabled: Bool { get set }
     var threadsEnabled: Bool { get set }
+    var isNewBloomEnabled: Bool { get set }
 }
 
 extension AppSettings: DeveloperOptionsProtocol { }