Managing servers remotely is a big usecase, and deploy-rs is a flake
first deployment tool. By default, all nixosConfigurations are also
setup as deploy-rs nodes.
You'll still need to do some manual ssh setup, but other than that, the
system is ready to deploy.
* Move extern lists to their own folder
* Move unstable package and module imports to their own folder
* Create a genPkgs function to avoid using legacyPackages for the whole
package set
* Move hmActivationPackages to legacyPackages