Initial setup of Docusaurus (#5227)

* Initial setup of Docusaurus

Followed steps on: https://docusaurus.io/docs/en/installation

* Delete doc1.md

* Delete doc2.md

* Delete doc3.md

* Delete exampledoc4.md

* Delete exampledoc5.md

website/sidebars.json

@@ -0,0 +1,10 @@
+{
+  "docs": {
+    "Docusaurus": ["doc1"],
+    "First Category": ["doc2"],
+    "Second Category": ["doc3"]
+  },
+  "docs-other": {
+    "First Category": ["doc4", "doc5"]
+  }
+}