Top level deeplink handling (#1660)

* Handle link opening on the top most levels and prepare for percolating them throughout the app
* Add support for a custom app scheme
* Add specific AppRoute parsers.
* Integrate custom scheme in the AppRouteURLParser
* Switch to `element://call` and cleanup route parsing

ElementX/Sources/UnitTests/UnitTestsAppCoordinator.swift

@@ -37,7 +37,7 @@ class UnitTestsAppCoordinator: AppCoordinatorProtocol {
         AnyView(ProgressView("Running Unit Tests"))
     }
     
-    func handleUniversalLink(_ url: URL) {
+    func handleDeepLink(_ url: URL) -> Bool {
         fatalError("Not implemented.")
     }
 }