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/Trello.js

@@ -0,0 +1,39 @@
+// @flow
+import * as React from 'react';
+import Frame from './components/Frame';
+
+const URL_REGEX = /^https:\/\/trello.com\/(c|b)\/(.*)$/;
+
+type Props = {
+  url: string,
+  matches: string[],
+};
+
+export default class Trello extends React.Component<Props> {
+  static ENABLED = [URL_REGEX];
+
+  render() {
+    const { matches } = this.props;
+    const objectId = matches[2];
+
+    if (matches[1] === 'c') {
+      return (
+        <Frame
+          width="316px"
+          height="158px"
+          src={`https://trello.com/embed/card?id=${objectId}`}
+          title={`Trello Card (${objectId})`}
+        />
+      );
+    }
+
+    return (
+      <Frame
+        width="248px"
+        height="185px"
+        src={`https://trello.com/embed/board?id=${objectId}`}
+        title={`Trello Board (${objectId})`}
+      />
+    );
+  }
+}