refactor: replace custom CRM with Monica fork

resources/views/errors/503.blade.php

@@ -0,0 +1,12 @@
+@extends('errors::layout')
+
+@section('title', trans('app.error_unavailable'))
+
+@section('message', trans('app.error_maintenance'))
+
+@section('content')
+  <p>
+      @lang('app.error_help')
+      @lang('app.error_twitter', ['twitter' => config('monica.twitter_account')])
+  </p>
+@endsection