Run sample with some errors on console of devtools.

[liudonghua123]

Hi, I tried to run the sample, but I saw some errors related to http://localhost:8080/manifest.json, http://localhost:8080/myExt/nls.metadata.json 404 Not Found!

Steps of reproduce.

1. git clone git@github.com:Felx-B/vscode-web.git
2. cd vscode-web/sample
3. yarn
4. yarn sample
5. Open http://localhost:8080 in browser.

[liudonghua123]

I also noticed that Sample project can be found in this repository to illustate vscode-web usage. This sample is not fully functional as it misses a FileSystemProvider extension. in the readme.

It seems has no direct effection on /manifest.json and /myExt/nls.metadata.json.