Nightly publication of pre-release

[lhstrh]

This PR enables the nightly publication of a pre-release of the VS Code extension.

The version of the published artifact is always current-major-next-minor-yyyymmdd and always uses the latest version of lingua-franca found on the master branch. No git tags are produced.

Other things done:

• [x] removal of build workflow, because it was no longer used
• [x] refactoring of build action to no longer do checkout
• [x] refactoring of existing workflows to refer to build action in the local filesystem
• [x] refactoring of scripts in package.json so that building is now separate from deploying

[lhstrh]

I did not understand all of the bash scripting that was added in build/action.yml but everything else looks good to me.

That's just for installing code, which is needed for npm run build.