it's unused atm

Instead of hardcoding the paths of the node_modules directory we use the node-resolve
plugin of rollup to find the root of the corresponding JS package and calcucate a path from
there.

Resolving a package requires calling an async function, so we have to use await in the rollup config.
Luckily rollup supports configs wrapped in a promise, so we just have to wrap it in a function which returns
a promise.

Since they are no longer in separate repos we no longer need the
gitlab CI config files.

We couldn't do this until now because we referenced them by a relative path with npm.
But now that we reference them by name and yarn handles the linking we can
specify them as normal dependencies.

This is the lock file used by npm