Editor embeds (#680)

- [x] Make deleting an embed easier
- [x] Add document level ability to disable embeds
- [x] Add team level ability to disable embeds
- [x] GitHub
- [x] Numeracy
- [x] Mode Analytics
- [x] Figma
- [x] Airtable
- [x] Vimeo
- [x] RealtimeBoard
- [x] Loom
- [x] Lucidcharts
- [x] Framer
- [x] InVision
- [x] Typeform
- [x] Marvel
- [x] Spotify
- [x] Codepen
- [x] Trello

app/embeds/Codepen.js

@@ -0,0 +1,19 @@
+// @flow
+import * as React from 'react';
+import Frame from './components/Frame';
+
+const URL_REGEX = new RegExp('^https://codepen.io/(.*?)/(pen|embed)/(.*)$');
+
+type Props = {
+  url: string,
+};
+
+export default class Codepen extends React.Component<Props> {
+  static ENABLED = [URL_REGEX];
+
+  render() {
+    const normalizedUrl = this.props.url.replace(/\/pen\//, '/embed/');
+
+    return <Frame src={normalizedUrl} title="Codepen Embed" />;
+  }
+}