Operator should support Istio sidecars

[jsenko]

Analyze whether the support for Istio sidecars requires any changes to the operator, and in either case document steps to set it up.

See

• https://istio.io/latest/docs/setup/additional-setup/sidecar-injection
• adding istio sidecar to apicurio instance apicurio-registry-operator#259

CC @L040639