Draft: feat: POC adding the LS Duo Chat Webview

DO NOT MERGE

ls-webview-duo-chat

How to run locally

Language server

1. checkout js/webview-experiment branch
2. go to webview/example and run npm i && npm run build
3. from project root run npm run compile && npm run bundle:desktop && yalc publish

VS Code extension

1. checkout this MR branch
2. run yalc add @gitlab-org/gitlab-lsp && npm i
3. start the extension as you normally would