Epic: Upgrade-Manager V2 and v1alpha2

[eytan-avisror]

We would like to re-write the upgrade-manager controller in order to take better advantage of controller-runtime reconciler and handling of state changes.

Currently the controller creates a goroutine to process the rotation when the CR is created and exits once the operation is complete - and does not continually reconcile the custom resource. - This is causing a lot of issues around stale state - e.g. If an ASG instance state has changed, we never know about it.

If we constantly reconcile the CR by checking the state, moving rotation forward, and requeuing the CR - we would have much more accurate state with potentially more efficient API calls.

Suggestion is to re-write the controller, and utilize existing code as much as possible and implement the same API used in v1alpha1.

As a second step, we should consider adding v1alpha2 with API improvements.

[eytan-avisror]

@uthark FYI
We are starting this work on branch controller-v2, we will add you as reviewer before we merge (currently we just got started).
High level goals are refactoring code for maintainability, better package structure, and better state handling / reconcile / caching.