feat: Add CDN support (#1817)

* chore: CSP

* chore: Optionally use CDN for serving images

server/emails/components/Header.js

@@ -3,6 +3,8 @@ import { Table, TBody, TR, TD } from "oy-vey";
 import * as React from "react";
 import EmptySpace from "./EmptySpace";
 
+const url = process.env.CDN_URL || process.env.URL;
+
 export default () => {
   return (
     <Table width="100%">
@@ -12,7 +14,7 @@ export default () => {
             <EmptySpace height={40} />
             <img
               alt="Outline"
-              src={`${process.env.URL}/email/header-logo.png`}
+              src={`${url}/email/header-logo.png`}
               height="48"
               width="48"
             />