Consistent names of our labels.

[vaikas]

Expected Behavior

Our labels should follow the convention of eventing.knative.dev/something just like serving.knative.dev/route for example.

Actual Behavior

At least some of them don't.
See discussion:
#674 (comment)

Additional Info

[Harwayne]

This came up again in #698. I believe the procedure to safely change the labels is:

1. Change CreateVirtualService to compare labels, in addition to the current comparing spec. If the labels differ, update the VirtualService.

2. Change CreateK8sService to act like CreateVirtualService, in that it compares the existing to the desired and updates existing to match desired.

3. Add the new labels to all created Services and VirtualServices. But, only search for them based on the old labels (i.e. getK8sService and getVirtualService use a label selector that only uses the old labels).

   • The combination of this and the previous two steps means that existing Services and VirtualServices will get the updated labels added.

4. Wait a full release.

5. No longer search for or create using the old labels.

[sbezverk]

/assign @sbezverk