Access Ironic API via OOB network on shared interface

[fzakfeld]

As discussed with @berendt, I'd like to have the possibility to access the Metalbox Ironic API via the OOB interface. Our servers have a shared OOB + Inband Port, so the setup can be simplified without the need to connect the metalbox to the BGP (Inband) setup.

The ULA fd33:fd0e:2aee::42/128 is currently on the metalbox virtual interface for BGP. There should be the option to add this to the OOB Interface on (not of) the metalbox, e. g. vlan123@Ethernet1 and as a /64.

Perhaps we can use a tag on the interface (with no tag meaning the metalbox interface is used) and determine the use of /64 vs /128 by the fact that metalbox is a dummy?

[fzakfeld]

(To be clear, the IPA image also needs changes for this, but this is just for the inventory / netplan config part)