Support deployment type deletion

[ayalash]

Applications some times are being replaced by other applications.
It would be great if there will be an API for deleting all the information of an old application (for site admins only).
The API should:

1. Verify not deployments of this application installed.
2. Delete all the DB objects that belongs to this application: deployment_kind, deployments, helm_registries, helm_charts , deployment_tasks, deployment_permissions.

@popen2 What do you think about this feature request?