Add config map support for PrivateDnsZonesARecord

[nraooptum]

When we create a private endpoint, we're able to output the primaryNicPrivateIpAddress to a config map. However, PrivateDnsZonesARecord doesn't support config maps as input for the ipv4Address field.

[matthchr]

@super-harsh is going to look into this, or if there is a better way to do this using the infrastructure that Azure provides (I thought there was a way to get this done automatically but need to look more).

[nraooptum]

Perfect! Thank you both! In the interim, would the ipv4Address field be compatible with the $importConfigMapMode option?

[matthchr]

I haven't had a chance to look into this further but just making a note we haven't forgotten.

[nraooptum]

Thanks for the follow up Matt!

[nraooptum]

@matthchr good news, our enterprise is adopting ASO as the way forward 👍 This passed our internal Architecture Review Board and everyone is excited to start migrating over to this.
 
Random side note, I was thinking, you know how we can export arbitrary values from a resource, e.g.:
https://azure.github.io/azure-service-operator/guide/configmaps/

Instead of having to implement $importConfigMapMode for a bunch of different things, what if we had the option of applying patches? For example (just making something up):

  operatorSpec:
    patchExpressions:
      - patchField: self.spec.aRecords[0].ipv4Address
        configMapName: some-configmap
        configMapKey: myIpV4Address

This would make it generic enough to pass stuff around even when the resource doesn't natively "support" injecting a value from a config map, especially when combined with the ability to export anything using configMapExpressions.