feat: Add CDN support (#1817)

* chore: CSP

* chore: Optionally use CDN for serving images

app/components/Editor.js

@@ -8,9 +8,9 @@ import UiStore from "stores/UiStore";
 import ErrorBoundary from "components/ErrorBoundary";
 import Tooltip from "components/Tooltip";
 import embeds from "../embeds";
-import isInternalUrl from "utils/isInternalUrl";
 import { isMetaKey } from "utils/keyboard";
 import { uploadFile } from "utils/uploadFile";
+import { isInternalUrl } from "utils/urls";
 
 const RichMarkdownEditor = React.lazy(() => import("rich-markdown-editor"));