Feat(Gotenberg): Opt-in alternative pdf generation for modern CSS (#184)

* WIP(gotenberg): add pdf generation abstraction and UI

* feat(pdf): settings validate(clien+server) & save

* fix(gotenberg): Use correct default papersize
chore(gotengberg): Remove unused GOTENBERG_MARGINS env from .env

* style(gotenberg): fix linter/styling issues

* fix(pdf): use pdf config policy

* fix: revert accidental capitalization in mail config vue

* Update composer, remove whitespace typo

* Fix small typos

* fix cookie/env issue

* Add gotenberg to .dev, move admin menu item up

app/Http/Requests/PDFConfigurationRequest.php

@@ -0,0 +1,57 @@
+<?php
+
+namespace App\Http\Requests;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class PDFConfigurationRequest extends FormRequest
+{
+    /**
+     * Determine if the user is authorized to make this request.
+     */
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    /**
+     * Get the validation rules that apply to the request.
+     */
+    public function rules(): array
+    {
+        switch ($this->get('pdf_driver')) {
+            case 'dompdf':
+                return [
+                    'pdf_driver' => [
+                        'required',
+                        'string',
+                    ],
+                ];
+                break;
+
+            case 'gotenberg':
+                return [
+                    'pdf_driver' => [
+                        'required',
+                        'string',
+                    ],
+                    'gotenberg_host' => [
+                        'required',
+                        'url',
+                    ],
+                    'gotenberg_papersize' => [
+                        function ($attribute, $value, $fail) {
+                            ($attribute); // unused
+                            $reg = "/^\d+(pt|px|pc|mm|cm|in) \d+(pt|px|pc|mm|cm|in)$/";
+                            if (! preg_match($reg, $value)) {
+                                $fail('Invalid papersize, must be in format "210mm 297mm". Accepts: pt,px,pc,mm,cm,in');
+                            }
+                        },
+                    ],
+                ];
+
+                break;
+        }
+        throw new \InvalidArgumentException('Invalid PDFDriver requested');
+    }
+}