Update setup and createTable tutorial to 100% Sandy

Summary:
The current desktop plugin tutorial was outdated as it has several steps that are now automated, and still referred to old APIs. This has been updated now.

Additionally left the intermediate code of the tutorial in the plugin, but splitting `index.tsx` into `index_table.tsx` and `index_custom.tsx` (which will be updated in the next diff)

Clarified the tutorial page labels a little bit to show that 3 pages are covering the Desktop plugin development process.

Changelog: Updated the Desktop plugin tutorial

Reviewed By: jknoxville

Differential Revision: D28990029

fbshipit-source-id: a06a7a774ceca3daf10f8e8fbd4e03191dbfd1cc

website/sidebars.js

@@ -120,7 +120,6 @@ module.exports = {
     'Desktop plugin APIs': [
       'extending/flipper-plugin',
       'extending/styling-components',
-      'extending/create-table-plugin',
       'extending/search-and-filter',
       ...fbInternalOnly([
         {
@@ -131,6 +130,7 @@ module.exports = {
         'Deprecated APIs': [
           'extending/ui-components',
           'extending/js-plugin-api',
+          'extending/create-table-plugin',
         ],
       },
     ],