Introduce ConfiguredController concept

[snowdrop-bot]

The idea is to expand on the ControllerRef class to associate a controller with its configuration and propagate this entity instead of passing the controller, the configuration and very often the kube client to each object that needs that information.
See commit message on operator-framework@1c47ecf for more details.

Fixes operator-framework#496.

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operator-framework#517

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$upstream:517$