fix: allow publicIP to be referenced using selectors and Ref

[migueladh]

Description of your changes

• Add Reference Extractor for PublicIPAddressId in NetworkInterface, allowing the usage on dynamic objects
• Add example yaml

Fixes #78

I have:

• Run make reviewable test to ensure this PR is ready for review.

How has this code been tested

1. Run provider locally with the changes
2. Create the objects provided in the example file
3. Network interface will be correctly created with publicAddess

kubectl get networkinterface.network.azure.upbound.io/example -o yaml

apiVersion: network.azure.upbound.io/v1beta1
kind: NetworkInterface
metadata:
  annotations:
    crossplane.io/external-create-pending: "2024-02-15T11:51:47+01:00"
    crossplane.io/external-create-succeeded: "2024-02-15T11:51:47+01:00"
    crossplane.io/external-name: example
  creationTimestamp: "2024-02-15T10:49:34Z"
  finalizers:
  - finalizer.managedresource.crossplane.io
  generation: 3
  labels:
    testing.upbound.io/example-name: example
  name: example
  [...]
spec:
  deletionPolicy: Delete
  forProvider:
    ipConfiguration:
    - name: internal
      privateIpAddressAllocation: Dynamic
      publicIpAddressId: /subscriptions/XXXX/resourceGroups/XXXX/providers/Microsoft.Network/publicIPAddresses/example
      publicIpAddressIdRef:
        name: example
      publicIpAddressIdSelector:
        matchLabels:
          testing.upbound.io/example-name: example-public-ip
[...]

[Upbound-CLA]

All committers have signed the CLA.

[jeanduplessis]

/test-examples="examples/network/networkinterface-publicip.yaml"

[turkenf]

Thanks for your contribution @migueladh, left a few comments for you to consider.

[turkenf]

/test-examples="examples/network/networkinterface-publicip.yaml"

[turkenf]

@migueladh, I left two more small comments and please sign license/cla for moving forward.

[migueladh]

@turkenf sorry for the delay, all done :)

[turkenf]

/test-examples="examples/network/networkinterface-publicip.yaml"

[turkenf]

Thank you for your work in this PR @migueladh, LGTM.