Applying package with a stack is idempotent

[jsteenb2]

As a user,
I want to create resources with pkgs and a stack,
so that I don't have to clean up duplicates resources and declare a state of the world

This card is to add idempotency to pkger via a stack. A stack is the state that tracks the side effects of creating a package. Using this, we want to be able to apply packages idempotently and always end up with the state declared in the package.

idempotent means the following:

the state of the world is always accurate to the package. resources are uniquely identified via its kind and metadata.name fields. Any and all secondary resources created (i.e. label mappings) are accurate to the package.

AC

• stacks are used when a stack ID is provided to the dry run/apply functionality
  • extends HTTP POST /api/v2/packages with stack_id field
• package payload is optional if stack_id is provided and stack has URL(s) associated with it
• stacks are updated when side effects are created, if nothing changed between state of the world and package stack is not updated.
• resources are applied idempotently
  • labels
  • buckets
  • checks
  • dashboards
  • notification endpoints
  • notification rules
  • tasks
  • telegraf
  • variable
• when an association is removed in pkg, is also removed from platform
• support use cases where elements have been deleted by user