Add docs sidebar (#11817)

* Brings pairity for doc checks from cloud

* WIP Sidebar config

It's sketchy JSON let's commit before we break i

* MVP sidebars

summary.md is no longer functional
it's higherarchy was translated into sidebar.js
as a JSON format that docusaurus likes

* Removes another unused readme

docs/connector-development/tutorials/README.md

@@ -1,2 +0,0 @@
-# Tutorials
-