See https://github.com/NixOS/nixpkgs/issues/437208#issuecomment-3288623669
Depends on https://github.com/NixOS/org/pull/172
As documented below, the idea is to essentially group all changes
rebuilding all VM tests with kernel updates and merge them together into
`master` whenever the Linux kernels get updated.
This documents the workflow of updates in the nixpkgs manual. While at
it, I removed the README from the packages because
* it's horribly outdated
* I didn't even know it exists which confirms that its discoverability
was very poor
and added the relevant portions into the nixpkgs manual as well.