Rename Size to Replicas

[jpkrohling]

From #207 (comment)

[jpkrohling]

Should we keep Size for backwards compatibility?

cc @objectiser, @pavolloffay

[objectiser]

I guess as the apiGroup has changed, then we could make this a breaking change (clearly marked in changelog)? Although in general if it doesn't complicate code too much, it would be easier to deprecate.

[jpkrohling]

It requires both options to co-exist. Right now, the migration path from the old apiGroup to the new one is changing from io.jaegertracing to jaegertracing.io in the CR files.

Edit: expanding a bit on the above, here's what it would look like to have both.

The types, such as JaegerCollectorSpec would look like this:

// JaegerCollectorSpec defines the options to be used when deploying the collector
type JaegerCollectorSpec struct {
	// Size represents the number of replicas to create for this service. DEPRECATED, use `Replicas` instead.
	Size int `json:"size"`

	// Replicas represents the number of replicas to create for this service.
	Replicas *int `json:"replicas"`

	Image   string  `json:"image"`
	Options Options `json:"options"`
	JaegerCommonSpec
}

Then, functions like NewCollector would look like this:

// NewCollector builds a new Collector struct based on the given spec
func NewCollector(jaeger *v1.Jaeger) *Collector {
	if jaeger.Spec.Collector.Replicas == nil {
		replicaSize := 1
		if jaeger.Spec.Collector.Size > 0 {
			replicaSize = jaeger.Spec.Collector.Size
		}

		jaeger.Spec.Collector.Replicas = &replicaSize
	}

	if jaeger.Spec.Collector.Image == "" {
		jaeger.Spec.Collector.Image = fmt.Sprintf("%s:%s", viper.GetString("jaeger-collector-image"), viper.GetString("jaeger-version"))
	}

	return &Collector{jaeger: jaeger}
}