feat: add skipNpmInstall option

[DerZade]

This PR adds a skipInstallDeps option (false by default), which allows to skip the npm install step (or whatever package manager you're using).

Motivation

I would like to include a prepare-script in an npm package. This prepare-script runs automatically during npm install, which I would like to avoid.

[CLAassistant]

All committers have signed the CLA.

[dsherret]

Seems reasonable, but this also means that type checking or tests will likely fail. Probably what would be best is to edit the package.json to add the prepare script in the postBuild hook.