[10.x] Uses PHP Native Type Declarations 🐘 (#6010)

* Adds basic typing around method's arguments and return types

* Adds missing `closure` type

* Adds typing on tests

* Fixes `RedirectIfAuthenticated`

* Fixes `Authenticate`

* Improves `RedirectIfAuthenticated` types

* Fixes user factory `unverified` return type

app/Http/Middleware/TrustHosts.php

@@ -11,7 +11,7 @@ class TrustHosts extends Middleware
      *
      * @return array<int, string|null>
      */
-    public function hosts()
+    public function hosts(): array
     {
         return [
             $this->allSubdomainsOfApplicationUrl(),