feat: Organizational RunnerDeployment Autoscaling

Enhances #57 to add support for organizational runners.

As GitHub Actions does not have an appropriate API for this, this is the spec you need:

```
apiVersion: actions.summerwind.dev/v1alpha1
kind: RunnerDeployment
metadata:
  name: myrunners
spec:
  minReplicas: 1
  maxReplicas: 3
  autoscaling:
    metrics:
    - type: TotalNumberOfQueuedAndProgressingWorkflowRuns
      repositories:
      # Assumes that you have `github.com/myorg/myrepo1` repo
      - myrepo1
      - myrepo2
  template:
    spec:
      organization: myorg
```

It works by collecting "in_progress" and "queued" workflow runs for the repositories `myrepo1` and `myrepo2` to autoscale the number of replicas, assuming you have this organizational runner deployment only for those two repositories.

For example, if `myrepo1` had 1 `in_progress` and 2 `queued` workflow runs, and `myrepo2` had 4 `in_progress` and 8 `queued` workflow runs at the time of running the reconcilation loop on the runner deployment, it will scale replicas to 1 + 2 + 4 + 8 = 15.

Perhaps we might be better add a kind of "ratio" setting so that you can configure the controller to create e.g. 2x runners than demanded. But that's another story.

Ref #10

controllers/runnerdeployment_controller.go

@@ -99,9 +99,7 @@ func (r *RunnerDeploymentReconciler) Reconcile(req ctrl.Request) (ctrl.Result, e
 
 	desiredRS, err := r.newRunnerReplicaSetWithAutoscaling(rd)
 	if err != nil {
-		if _, ok := err.(NotSupported); ok {
-			r.Recorder.Event(&rd, corev1.EventTypeNormal, "RunnerReplicaSetAutoScaleNotSupported", err.Error())
-		}
+		r.Recorder.Event(&rd, corev1.EventTypeNormal, "RunnerAutoscalingFailure", err.Error())
 
 		log.Error(err, "Could not create runnerreplicaset")