feat(cms): white-label email templates and API doc config

Replace all hardcoded muellerprints brand identity in email templates
with template variables (shopName, shopContactName, shopAddress,
shopPhone, shopEmail, shopLogoUrl, shopSecondaryLogoUrl) sourced from
env vars SHOP_NAME, SHOP_CONTACT_NAME, SHOP_ADDRESS, SHOP_PHONE,
SHOP_EMAIL, SHOP_LOGO_URL, SHOP_SECONDARY_LOGO_URL.

API documentation title/description now driven by API_TITLE and
API_DESCRIPTION env vars.

Closes #1

src/extensions/documentation/config/settings.json

@@ -2,8 +2,8 @@
 	"openapi": "3.0.1",
 	"info": {
 		"version": "1.0.0",
-		"title": "MUELLERPTINTS. Paperwork",
-		"description": "API Documentation for MUELLERPRINTS. Paperwork",
+		"title": "Paperwork API",
+		"description": "Paperwork API",
 		"termsOfService": false,
 		"contact": false,
 		"license": false