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

resources/scripts/admin/views/installation/Step8CompanyPreferences.vue

@@ -162,7 +162,7 @@ const isSaving = ref(false)
 let isFetchingInitialData = ref(false)
 
 let currentPreferences = reactive({
-  currency: 1,
+  currency: 3,
   language: 'en',
   carbon_date_format: 'd M Y',
   time_zone: 'UTC',