NetBox sites used for development testing included in release artifacts

[mmguero]

The latest release and possibly others unintentionally included a ./netbox/preload/sites.yml file (used by Malcolm developers for testing) in malcolm-25.08.0-docker_install.zip.

This had the unintended effect of preloading several sites into the NetBox database:

- name: Cyberville
  slug: cyberville
  status: active
- name: NEIN
  slug: nein
  status: active
- name: Virtual Boy
  slug: virtual-boy
  status: active
- name: Digital Bond S4
  slug: digital-bond
  status: active
- name: M57 Patents
  slug: m57-patents
  status: active
- name: Kitchen Sink
  slug: kitchen-sink
  status: active

There are no other functional or security implications of this inclusion: just the creation of unwanted site objects in netbox.

The scripts used to create these artifacts will be adjusted to ensure this doesn't happen again.