Added login redirect system to confirm/mfa

Also continued a bit on the MFA verification system.
Moved some MFA routes to public space using updated login service to get
the current user that is either logged in or last attempted login (With
correct creds).

app/Exceptions/StoppedAuthenticationException.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace BookStack\Exceptions;
+
+use BookStack\Auth\Access\LoginService;
+use BookStack\Auth\User;
+use Illuminate\Contracts\Support\Responsable;
+
+class StoppedAuthenticationException extends \Exception implements Responsable
+{
+
+    protected $user;
+    protected $loginService;
+
+    /**
+     * StoppedAuthenticationException constructor.
+     */
+    public function __construct(User $user, LoginService $loginService)
+    {
+        $this->user = $user;
+        $this->loginService = $loginService;
+        parent::__construct();
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function toResponse($request)
+    {
+        $redirect = '/login';
+
+        if ($this->loginService->awaitingEmailConfirmation($this->user)) {
+            $redirect = '/register/confirm/awaiting';
+        } else if  ($this->loginService->needsMfaVerification($this->user)) {
+            $redirect = '/mfa/verify';
+        }
+
+        return redirect($redirect);
+    }
+}