* Make dependabot check dependencies for NPM and composer
* Install JS dev requirements through package.json
This way we can have them automatically checked for newer versions.
* Add JS prod dependencies to packages.json for version tracking
They are added as optional dependencies, so we can skip their
installation with `--omit=optional` (as used in the Makefile), but we
can still have them checked for version updates automatically.
The package "publickey" is missing, because it's not available on
npmjs.com, but it hasn't seen updates in years anyway. We probably
should set up a different automatic check for updates nonetheless.
* Remove npm-related files when preparing packaging
