Add support for +mapType, +structType

[mariantalla]

The two annotations used to describe the topology of maps and structs, +mapType and +structType, should result in generating the equivalent openapi extensions (x-kubernetes-map-type and x-kubernetes-struct-type respectively). This is documented but not implemented at the moment.

/assign
(have a tiny PR in progress at the moment)

[sttts]

👍

[sttts]

Can you do the same addition to controller-tools? (compare kubernetes-sigs/controller-tools#345 for an example). I would like to make sure we use the same markers for both kube-openapi and kubebuilder's controller-tools.

cc @DirectXMan12

[mariantalla]

Yep, coming up next (sorry, should have created an issue 🤦‍♀ will go ahead and do that now). Thanks for the pointer too 🙏