NET-7178: add workload selector to MeshGateway protobuf definition

[NiniOak]

Description

This PR updates the MeshGateway protobuf definition to include workload selector. Another PR in Consul-K8s will build upon this to use this field but not add it to the meshgateway CRD

Testing & Reproduction steps

UI test passes
No linting errors

MeshGateway struct updates only. Validate the fields are updated correctly and CI/Lint pass

Links

PR Checklist

• updated test coverage
• external facing docs updated
• appropriate backport labels added
• not a security concern

[sarahalsmiller]

Hmm based on Nathan's comment here, I think you might need to break this out so it doesn't show up on the CRD. I couldn't find a kubetag that ignores a field completely, but it does look like you can set it to ignore unexported fields

[missylbytes]

Does that mean we would need to add the ignore option on the controller-gen command itself?

[nathancoleman]

I also couldn't find an option to ignore a single field; however, we paired as a group earlier today and worked through omitting the field in the consul-k8s CRD. We'll just use a different parent struct for the CRD in consul-k8s and then map that to a MeshGateway defined here by adding a workload selector before syncing into consul

[nathancoleman]

Nice work! Some optional commentary below but fine with this merging

[nathancoleman]

Stole the second line from other usages of this type across consul

Suggested change

	// Selection of workloads to be exposed through the MeshGateway
	// Selection of workloads to be configured as mesh gateways.
	// These can be prefixes or specific workload names.

[nathancoleman]

I also couldn't find an option to ignore a single field; however, we paired as a group earlier today and worked through omitting the field in the consul-k8s CRD. We'll just use a different parent struct for the CRD in consul-k8s and then map that to a MeshGateway defined here by adding a workload selector before syncing into consul