docs: integrate TypeDocs into vuepress output

# What's changed?

* create sidebar from typedoc output
* use plugin markdown to generate typedoc as markdown

docs/typedoc.json

@@ -0,0 +1,7 @@
+{
+  "$schema": "https://typedoc.org/schema.json",
+  "plugin": "typedoc-plugin-markdown",
+  "entryPoints": ["../packages/vue-flow/src/index.ts"],
+  "out": "src/typedocs",
+  "tsconfig": "../packages/vue-flow/tsconfig.docs.json"
+}