Collect up all the instances of clients (runtimeClient, corev1Client, apiClient ...) into a single struct

This was a useful update for maintenance purpose in [syndesis](https://github.com/syndesisio/syndesis/blob/1.15.x/install/operator/pkg/syndesis/clienttools/clienttools.go). It ensures that `clienttools` is passed around and the same clients are used throughout and always know where to get them from.