Introduce a `Ready` Condition

[jaypipes]

We currently have the ACK.ResourceSynced Condition that informs the Kubernetes user whether the desired state of a resource matches the latest observed state of the resource.

The ACK.ResourceSynced Condition is very much useful for both the ACK controllers as well as Kubernetes users, however this Condition does NOT represent the "readiness" of a particular AWS resource. By "readiness", I refer to the Kubernetes concept of readiness probes which allow a Kubernetes user to determine if a Pod is ready to accept incoming traffic/connections.

I believe we should have an ACK.Ready Condition that mimics this behaviour.

[RedbackThomson]

What would be the readiness for a static resource like an S3 bucket? Also for something stateful, like an RDS DBInstance, would ACK.Ready just imply the resource is in an accessible state (like Active) or something more?

[jaypipes]

What would be the readiness for a static resource like an S3 bucket?

For those kinds of resources, ResourceSynced and Ready would essentially be the same thing.

Also for something stateful, like an RDS DBInstance, would ACK.Ready just imply the resource is in an accessible state (like Active) or something more?

Precisely. When a DBInstance is in available state it would be Ready=True.

[vijtrip2]

/lifecycle frozen