[WIP] Disable cilium exclusive mode with multus

[hardys]

To align with https://docs.rke2.io/networking/multus_sriov#using-multus-with-cilium

In the long term it may be desirable to set this automatically via the RKE2 CAPI provider, but this seems like the simplest way to achieve the recommended configuration for now.

[hardys]

@alknopfler two questions when you get a moment:

• I think this should be included in all manifests, not just airgap right?
• If this should always be set for cilium+multus perhaps we should enable this via the RKE2 CAPI provider in future, what do you think?

[alknopfler]

yes, but I've modified in #12 the following scenarios in order to have more variety of use cases:

• Airgap with calico + multus because we've got a lot of scripts inside the ignition/combustion part
• Single node with calico + multus -> same reason
• Multi node cilium + multus -> I will add this code

makes sense?