horizontalpodautoscalers conflicts system generated annotations

Issue that we see, that Kapp seems to be clashing with system generated annotations.

Error:
```
Operation cannot be fulfilled on horizontalpodautoscalers.autoscaling "some-service": the object has been modified; please apply your changes to the latest version and try again (reason: Conflict)
```

Potential reason - Kapp detects system generated annotations as diffs and might detect a conflict:

```
- annotations:
- autoscaling.alpha.kubernetes.io/conditions: '[{"type":"AbleToScale","status":"True","lastTransitionTime":"2019-12-09T21:20:38Z","reason":"ScaleDownStabilized","message":"recent
- recommendations were higher than current one, applying the highest recent recommendation"},{"type":"ScalingActive","status":"True","lastTransitionTime":"2020-11-25T11:13:01Z","reason":"ValidMetricFound","message":"the
- HPA was able to successfully calculate a replica count from cpu resource utilization
- (percentage of request)"},{"type":"ScalingLimited","status":"True","lastTransitionTime":"2020-11-26T08:31:08Z","reason":"TooFewReplicas","message":"the
- desired replica count is less than the minimum replica count"}]'
- autoscaling.alpha.kubernetes.io/current-metrics: '[{"type":"Resource","resource":{"name":"cpu","currentAverageUtilization":0,"currentAverageValue":"2m"}}]'
```

Solution:
Kapp should ignore these fields