Scaffold out basic markdown language server (#154293)

* Scaffold out basic markdown lsp

This scaffolds out a new markdown language server and then uses it to implement document symbols. After the change, the markdown extension will have the following structure:

- languageService — Where all the LSP language stuff will eventually land
- server — The actual language server. Consumes ` languageService`
- src — The current extension that launches the server and implements VS Code specific functions

* Adding build scripts

* a

* Use language service from github

* Remove ls build scripts

* Bump versions

* Only build ext

* Enable for web

* Fixing for browser

extensions/markdown-language-features/server/tsconfig.json

@@ -0,0 +1,9 @@
+{
+	"extends": "../../tsconfig.base.json",
+	"compilerOptions": {
+		"outDir": "./out"
+	},
+	"include": [
+		"src/**/*"
+	]
+}