How to Support dynamically adding overriders

[CharlesQQ]

What would you like to be added:
We have a custom controller for Annotation-based gray code release; The different code release batch for cluster has the different metedata.annotation value, the value needs to be dynamically added in the overridepolicy and it's changed for each code release batch;

Why is this needed:
Support to dynamically add and complete this part of overriders before the work object is generated. I think of two ways to achieve this:

1. Add a new type of interpreter webhook
2. Allow user-defined controllers to watch overridepolicy's create/update events, and dynamically patch overriders, but it needs to be done before the work object is generated