Provide a way to create controllers for blue-green deployments

[PawelLipski]

@pawelprazak : possibly the piece for custom resources as seen here: https://github.com/amir/cr4s/blob/master/example/src/main/scala/Foo.scala could be used

[pawelprazak]

there's a very hacky PoC that shows why we need a controller/reconciler abstractions: https://github.com/VirtusLab/infrastructure-as-types/blob/feature-blue-green-poc/examples/src/main/scala/com.virtuslab.iat.examples/BlueGreen.scala https://github.com/VirtusLab/infrastructure-as-types/blob/feature-blue-green-poc/skuber/src/main/scala/com.virtuslab.iat.skuber/syntax.scala#L56

Related to #13