This reverts commit 42bfb73a06dca81e9e059efb47043df8054055b5.
For some reason, the iso is built every time, even when it doesn't
change, eating up all the space on cachix.
* Build a nixos configuration with all profiles available as part of ci
pipeline.
* Remove darwin packages as we do not have a ci agent for them.
* Build shell as part of ci