Add manager package and do some housekeeping

[jveski]

• Manager package constructs a ctrl.Manager for both integration tests and production use, and owns indices since they are manager-scoped (so shouldn't be owned by controllers)
• Converts PodCreation a pointer because there will be a period of time between allocating the struct and populating the creation timestamp
• Adds LastRolloutTime to synthesizer status in anticipation of the rollout mechanism
• Adds a custom log constructor to add controller name to the logs of each controller. This is better than just adding the fields within the Reconcile function because they will also be included when controller-runtime logs errors.
• Adds k8s version matrix to the integration tests in CI

[AYM1607]

Seems like some tests need field renaming, other than that, LGTM