Martin: I am looking at install_packages_to_data_dir.sh and I don't understand why we do that copying -> why aren't these packages just in data_dir from the start? Maybe because we want to make sure node_modules for each package are also not in there? But isn't there a better way to do this, maybe just by excluding node_modules? Then we don't have to do the whole building and copying and stuff, we actually don't have to do anything then.
Right now packages are .gitignored in data, and only their dist/ dir and package(-lock).json are in the waspc.cabal's data-files stanza, meaning that node_modules shouldn't be an issue.
So what I should try is moving packages from waspc/ to waspc/data, removing them from .gitignore in waspc/data, removing script install_packages..., adjusting code that calls it, and that is it! They should work! Aha, but we will still need to run npm install for each of them when we want to build the project, in order to make sure they are up to date (imagine checking out new version of them with not everything installed).