Change email confirmation from own middle to trait

Email confirmation middleware caused more mess than good, As caused
priority issues and it depended on auth actions. Instead its now a trai
used on auth middlewares.

Also used 'EncryptCookies' middleware on API instead of custom
decryption in custom middleware since we'd need to do replicate all the
same actions anyway. Shouldn't have too much effect since it only
actions over cookies that exist, of which none should be there for most
API requests.

Also split out some large guard functions to be a little more readable
and appease codeclimate.

app/Http/Middleware/ChecksForEmailConfirmation.php

@@ -0,0 +1,42 @@
+<?php
+
+namespace BookStack\Http\Middleware;
+
+use Illuminate\Http\Request;
+
+trait ChecksForEmailConfirmation
+{
+
+    /**
+     * Check if email confirmation is required and the current user is awaiting confirmation.
+     */
+    protected function awaitingEmailConfirmation(): bool
+    {
+        if (auth()->check()) {
+            $requireConfirmation = (setting('registration-confirmation') || setting('registration-restrict'));
+            if ($requireConfirmation && !auth()->user()->email_confirmed) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Provide an error response for when the current user's email is not confirmed
+     * in a system which requires it.
+     */
+    protected function emailConfirmationErrorResponse(Request $request)
+    {
+        if ($request->wantsJson()) {
+            return response()->json([
+                'error' => [
+                    'code' => 401,
+                    'message' => trans('errors.email_confirmation_awaiting')
+                ]
+            ], 401);
+        }
+
+        return redirect('/register/confirm/awaiting');
+    }
+}