Docs: Improve examples on overriding deployment resources

[oraNod]

Follows up on #20 (comment)

Purpose is to improve documentation in README at

awx-operator-helm/README.md

Line 249 in 70bac70

### Controller

While the example of the replica is valid. This is not really a common scenario to customize the operator replica (maybe to scale up/scale down). One more common use case is to specify a different container image for each container as seen in #17 or #27 to cover disconnected/restricted environments.
Another useful example would be to provide an example for setting up resource requests and limits, this would cover #14.