doc/website: migration to docosaurus v2 (#1384)

* WIP - migrating entgo.io to docosaurus v2

* organizing pages a bit to be better suited for v2 site structure

* doc/website: finish migration to docusaurus v2

Co-authored-by: Rotem Tamir <rotemtamir@gmail.com>

doc/website/sidebars.json

@@ -37,7 +37,7 @@
     ]
   },
   "tutorial": {
-    "Tutorial": [
+    "First Steps": [
       "tutorial-setup",
       "tutorial-todo-crud"
     ],