Reorganise for easier extraction

Summary:
To make the DataSource abstraction reusable for other teams and an upcoming talk, this diff moves all DataSource storage & virtualization logic in one folder.

Will set up a build process and demo project in later diffs.

Reviewed By: nikoant

Differential Revision: D28056700

fbshipit-source-id: 7cfe5b40bbbe387da711f765a604a45029d451c7

desktop/flipper-plugin/src/data-source/index.tsx

@@ -0,0 +1,15 @@
+/**
+ * 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
+ */
+
+export {DataSource} from './DataSource';
+export {
+  DataSourceRendererVirtual,
+  DataSourceVirtualizer,
+} from './DataSourceRendererVirtual';
+export {DataSourceRendererStatic} from './DataSourceRendererStatic';