perf: Reduce initial bundle size / async bundle loading (#1456)

* feat: Move to React.lazy

* perf: Remove duplicate babel/runtime

* fix: Run yarn-deduplicate

* Further attempts to remove rich-markdown-editor from initial chunk

* perf: Lazy loading of authenticated routes

* perf: Move color picker to async loading
fix: Display placeholder when loading rich editor

* fix: Cache bust on auto reload

app/components/FullscreenLoading.js

@@ -0,0 +1,24 @@
+// @flow
+import * as React from "react";
+import styled from "styled-components";
+import Empty from "components/Empty";
+import Fade from "components/Fade";
+import Flex from "components/Flex";
+
+export default function FullscreenLoading() {
+  return (
+    <Fade timing={500}>
+      <Centered>
+        <Empty>Loading…</Empty>
+      </Centered>
+    </Fade>
+  );
+}
+
+const Centered = styled(Flex)`
+  text-align: center;
+  width: 100%;
+  height: 100%;
+  align-items: center;
+  justify-content: center;
+`;