partial fix #5496: ipam: netbox: create / delete ip ranges for dhcp

partial fix #5496: ipam: netbox: create / delete ip ranges for dhcp

We use the IP ranges of netbox to represent the dhcp ranges. We were
already querying the IP ranges for a IP when starting a guest, but we
never created the IP ranges in the first place. Additionally implement
deleting the IP ranges when the subnet gets deleted.

These methods try to check for any possible errors before editing the
entities. There is still a small window where external changes can
occur that lead to errors. We are touching multiple entities here, so
in case of errors users have to fix their Netbox instance manually.

Signed-off-by: Stefan Hanreich <s.hanreich@proxmox.com>
Tested-by: Hannes Duerr <h.duerr@proxmox.com>
Link: https://lore.proxmox.com/20250310085103.30549-7-s.hanreich@proxmox.com
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>