Stub mesh configuration resource controller

[andrewstucki]

Changes proposed in this PR:

Adds basic stubbing/syncing of "MeshConfiguration" resources to Consul.

How I've tested this PR:

Manually created a CRD and saw it propagate to Consul:

apiVersion: mesh.consul.hashicorp.com/v2beta1
kind: MeshConfiguration
metadata:
  name: configuration

and then with consul resource list mesh.v2beta1.meshconfiguration:

{
    "resources": [
        {
            "data": {},
            "generation": "01HGXDYZTYK20821Q9Z6JMT9YS",
            "id": {
                "name": "configuration",
                "tenancy": {
                    "partition": "default",
                    "peerName": "local"
                },
                "type": {
                    "group": "mesh",
                    "groupVersion": "v2beta1",
                    "kind": "MeshConfiguration"
                },
                "uid": "01HGXDYZTYK20821Q9Z4BJPSHR"
            },
            "metadata": {
                "external-source": "kubernetes"
            },
            "version": "154"
        }
    ]
}

How I expect reviewers to test this PR:

Checklist:

• Tests added
• CHANGELOG entry added

[NiniOak]

Why use a blank identifier here as opposed to just removing the namespace parameter as it's no longer required?

[NiniOak]

Same question as above

[andrewstucki]

These are both to implement the ConsulResource interface found here -- it's what allows us to leverage the shared controller code:

consul-k8s/control-plane/api/common/consul_resource.go

Lines 15 to 16 in 46bf9bf

	ResourceID(namespace, partition string) *pbresource.ID
	Resource(namespace, partition string) *pbresource.Resource

So I need to keep the arguments even though they're unused since the resource is purely partition scoped (it doesn't have a namespace). It's a much less invasive change on the shared controller -- alternatively we'd need to make the shared code aware of resources that are partition-scoped and treat them differently.

[NiniOak]

Thanks for the explanation