Set up trusted publishing

[spoenemann]

• Use our new gh-publish-npm GitHub Action
  • See Langium’s publish.yml for an example
• Set up trusted publishing with OIDC:
  • Log in to npmjs.org and go to the Settings page of your package
• I already prepared a publish environment that can be used in the Actions workflow and the npm trusted publisher.
  • We need to add access tokens for VS Code Marketplace and Open VSX