Switch most remaining extensions to use esbuild

Just 3 left:

- git and github. These are doing weird stuff with d.ts imports and const enums

- github-authentication  which has some tricky path mapping stuff

extensions/ipynb/.vscodeignore

@@ -3,8 +3,6 @@ src/**
 notebook-src/**
 out/**
 tsconfig*.json
-extension.webpack.config.js
-extension-browser.webpack.config.js
+esbuild*.mts
 package-lock.json
 .gitignore
-esbuild.*