WIP GRPC rate limiting

[sarahalsmiller]

Changes proposed in this PR:

How I've tested this PR:

How I expect reviewers to test this PR:

Links

• https://pkg.go.dev/github.com/hashicorp/consul/api#CatalogRegistration
• https://pkg.go.dev/github.com/hashicorp/consul/api#CatalogDeregistration

Checklist:

• Tests added
• CHANGELOG entry added

  Run make changelog-entry for guidance in authoring a changelog entry, and
  commit the resulting file, which should have a name matching your PR number.
  Entries should use imperative present tense (e.g. Add support for...)

[mikemorris]

Suggested change

	```release-note:bug
	Use Consul Catalog API instead of Agent API to register APIGateway to prevent GRPC rate limits
	```
	```release-note:bug
	Use Consul Catalog API instead of Agent API to register gateways in agentless deployments, to avoid gRPC rate limiting for subsequent API calls handled by Consul servers other than the one with which the gateway was registered