Istio compatability takeover

[seekermarcel]

this is a takeover of #915 since we need it and the dev is unreachable.

should close zalando/postgres-operator#1629

also a continuation of #1082 because I deleted my fork accidentally

[zalando-robot]

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[seekermarcel]

@FxKu @middagj @hughcapet
sry for the hustle of recreating, but this is still relevant. would you check, test, label and approve this? thank you very much in advance