CKS registry and state updates

[JSpon]

Add registry credentials to cks creation, and caàtch failures on creation on for better state

[CodeBleu]

@JSpon Thanks for your contribution. Can you please add tests for this? It's also good to follow this once you've added your tests as this can help catch things before the github workflow runs it.

[kiranchavala]

@JSpon also can you add the documentation for the parameters

https://registry.terraform.io/providers/cloudstack/cloudstack/latest/docs/resources/kubernetes_cluster

[vishesh92]

@JSpon Please you update the documentation as well.

[Copilot]

Pull Request Overview

This PR adds Docker registry credential support to CloudStack Kubernetes cluster creation and improves error handling by attempting to retrieve cluster information when creation fails.

• Adds three new optional schema fields for Docker registry credentials (URL, username, password)
• Sets Docker registry parameters in the creation request when provided
• Implements error recovery by attempting to retrieve cluster information on creation failure

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[Copilot]

Setting the resource ID on creation failure is incorrect. This creates inconsistent state where Terraform believes the resource was created successfully but the actual creation failed. The original error should be returned without setting the ID, allowing Terraform to properly handle the failed creation.

Suggested change

	cluster, _, errg := cs.Kubernetes.GetKubernetesClusterByName(
	name,
	cloudstack.WithProject(d.Get("project").(string)),
	)
	if errg == nil {
	d.SetId(cluster.Id)
	}

[Copilot]

The docker_registry_password field should include DiffSuppressOnRefresh: true to prevent sensitive values from being stored in state and logged during refresh operations.

Suggested change

	"docker_registry_password": {
	Type: schema.TypeString,
	Optional: true,
	ForceNew: true,
	Sensitive: true,
	Sensitive: true,
	DiffSuppressOnRefresh: true,