ReconcilerStatus attribute naming

[pebrc]

Part of #1141

// ReconcilerStatus represents status information about desired/available nodes.
type ReconcilerStatus struct {
	AvailableNodes int `json:"availableNodes,omitempty"`
}

It was suggested by @nkvoll to rename this attribute to ReadyPods instead of AvailableNodes because the latter is imprecise as it is not clear what is meant with nodes and what available means.

The suggestion is also to add an additional attribute representing the desired pods e.g. pods so that we can generate a print column similar to what built-in resources have:

NAME                   HEALTH    READY     VERSION   PHASE               AGE
elasticsearch-sample   green     2/3         7.3.0   ApplyingChanges     12h

[pebrc]

additionalPrinterColumns can only be simple JSON path expressions so the suggested fractional syntax is not possible it seems.

[thbkrkr]

additionalPrinterColumns can only be simple JSON path expressions so the suggested fractional syntax is not possible it seems.

What if we maintain a string field in the ReconcilerStatus computed from the number of ready pods and desired pods:

type ReconcilerStatus struct {
	AvailableNodes int32  `json:"availableNodes,omitempty"`
	ReadyPods      int32  `json:"readyPods,omitempty"`
	DesiredPods    int32  `json:"desiredPods,omitempty"`
	PodCounter     string `json:"podCounter,omitempty"` # <---
}