Disable creation of new Kubernetes Integrations unless they are active and created from template

We are in process of removing Kubernetes Integration as all the functionality is superseded by Clusters::Cluster.

In order to remove this functionality and be replaced, we should:

• disallow creation of new Kubernetes Integrations,
• once disabled we should disallow to enable them and guide people to use a new User Clusters (CI/CD > Clusters),
• Kubernetes integration could be edited only if it is accessed from Application Templates (Admin Area).

Proposal

1. Leave the service integration list untouched (still showing Kubernetes integration there)
2. In the service integration detail page, show a banner announcing the deprecation and the new page link
3. Make banner copy dynamic depending on the service status.

• If the service is inactive: "Kubernetes service integration has been deprecated. Fields on this page are now uneditable, you can configure your clusters using the new <a href=\"#{project_url}/clusters\">Clusters</a> page"
• If the service is active: "Kubernetes service integration has been deprecated. Your cluster information on this page is still editable, but you are advised to disable and reconfigure your clusters using the new Clusters page"

1. If the service is inactive make the form fields read-only (disabled)
2. If the service is active the form fields are editable
3. Service template is kept untouched.