Use app http settings for status, WebSockets

[bollwyvl]

References

• fixes Use the host application's server connection settings #880

Code changes

• initialize LanguageServerManager with app.serviceManager.settingsis being used
• use these settings for doing API requests and WebSockets
• handle a race condition for very fast settings loading (no http request) for plugins with a PromiseDelegate
• rev some node versions (not sad about retiring 14 a little early)
• resolve and deduplicate yarn.lock: get "one true version" of typescript, prettier, webpack
• use webpack 5 for lsp-ws-connection
• add sourcemaps (we can take these out, but... would be really nice for downstream debugging)
• refresh robot tooling

User-facing changes

• hopefully few visible changes

Backwards-incompatible changes

• hopefully none: no signatures were changed

Chores

• linted
• tested
• documented
• changelog entry

[github-actions]

👈 Launch a binder notebook on branch bollwyvl/jupyterlab-lsp/gh-880-use-app-http-settings

[krassowski]

I will get #869 in to help with CI.

[bollwyvl]

Sure I'll take all the help I can get! Would love to add lite to the docs site once I get this all sorted out and get something running.

[bollwyvl]

With #869 looking good, i'll rebase on top of that.