Show FB internal instructions by default on "Getting Started" page

Summary:
Show internal instructions for Flipper setup by default on "Getting Started" page. This is a follow up to https://fb.workplace.com/groups/flippersupport/permalink/955763464904312/.

I used tabs component to show both internal and external content in tabs. By default, internal content is shown, but it is possible to also switch to external.

Reviewed By: jknoxville

Differential Revision: D23649955

fbshipit-source-id: c4f956e0ee9fec69cf861d96a447f934f746dd7f

website/src/components/FBContent.jsx

@@ -0,0 +1,48 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+import React from 'react';
+import {isInternal} from 'internaldocs-fb-helpers';
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+
+function createElement(createElement) {
+  if (!createElement) return undefined;
+  if (React.isValidElement(createElement)) {
+    return createElement;
+  }
+  const element = createElement();
+  if (React.isValidElement(element)) {
+    return element;
+  }
+  return React.createElement(element.default || element, {});
+}
+
+function FBContent({internal, external}) {
+  if (!isInternal()) {
+    return createElement(external);
+  }
+  if (internal && external) {
+    return (
+      <Tabs
+        defaultValue="internal-docs"
+        values={[
+          {label: 'FB Internal', value: 'internal-docs'},
+          {label: 'Open-Source', value: 'external-docs'},
+        ]}>
+        <TabItem value="internal-docs">{createElement(internal)}</TabItem>
+        <TabItem value="external-docs">{createElement(external)}</TabItem>
+      </Tabs>
+    );
+  } else {
+    return createElement(internal || external);
+  }
+}
+
+export default FBContent;