Zapier integration (#491)

* create zapier app

* install sanctum

* move OAuthProviderController

* make `api-external` middleware

* add zapier endpoints

* add tests

* token management

* zapier event handler

* add policy

* use `slug` instead of `id`

* wip

* check policies

* change api prefix to `external`

* ui tweaks

* validate token abilities

* open zapier URL

* zapier ui tweaks

* update zap

* Fix linting

* Added sample endpoints + minor UI changes

* Run PHP code linter

---------

Co-authored-by: Julien Nahum <julien@nahum.net>

app/Http/Controllers/Integrations/Zapier/ValidateAuthController.php

@@ -0,0 +1,18 @@
+<?php
+
+namespace App\Http\Controllers\Integrations\Zapier;
+
+use Illuminate\Support\Facades\Auth;
+
+class ValidateAuthController
+{
+    public function __invoke()
+    {
+        $user = Auth::user();
+
+        return [
+            'name' => $user->name,
+            'email' => $user->email,
+        ];
+    }
+}