Remove dynamic /etc/os-release creation

[smira]

Code: https://github.com/siderolabs/talos/blob/1fb8453c2db1659dd6c1670e4174125b26e777c5/internal/app/machined/pkg/runtime/v1alpha1/v1alpha1_sequencer_tasks.go#L387-L401

Instead of writing it down dynamic way with a bind mount, go generate the file contents, and make it part of rootfs and read-only.

Remove the task.