Configurations cleanup & database configurations for mail and pdfs (#479)

* Move Mail, PDF configuration to Database, standardize configurations

* Set default currency to USD on install

* Pint code

bootstrap/providers.php

@@ -6,4 +6,5 @@ return [
     App\Providers\DropboxServiceProvider::class,
     App\Providers\ViewServiceProvider::class,
     App\Providers\PDFServiceProvider::class,
+    App\Providers\AppConfigProvider::class,
 ];