refactor(router): Add opt-in provider for upcoming router change (#47988)

This commit adds a swappable provider for an upcoming change to the
implementation of `Router#createUrlTree`. This will be a breaking change
and is planned to be included in V16.

PR Close #47988

packages/core/test/bundling/router/bundle.golden_symbols.json

@@ -110,6 +110,9 @@
   {
     "name": "Console"
   },
+  {
+    "name": "CreateUrlTreeStrategy"
+  },
   {
     "name": "DEFAULT_SERIALIZER"
   },
@@ -251,6 +254,9 @@
   {
     "name": "LQuery_"
   },
+  {
+    "name": "LegacyCreateUrlTree"
+  },
   {
     "name": "LifecycleHooksFeature"
   },