Drop controller-runtime dependency

[maiqueb]

Hey,

I've started not long ago a prototype of a reconcile loop for IP addresses for whereabouts IPPools in PR #185 . The approach I'm using just uses the informer / lister / clientSet Kubernetes library objects, which I'm introducing in PR #202 .

If we add these library objects to the github repo, we can drop the controller-runtime dependency - I've ran a couple of times already into some vendoring related issues around it.

Another option would be to - instead of removing the dependency - use more if it, and manage the informers / cache objects through its framework, rather than via these library objects.

The former option seems more in line with the k8snetworkplumbingwg projects, since it is used (at least) in:

• https://github.com/k8snetworkplumbingwg/network-resources-injector
• https://github.com/k8snetworkplumbingwg/multi-networkpolicy-iptables

[dougbtv]

I'm in favor of trying to have some normalization across the NPWG (k8snetworkplumbingwg) projects. So, if we think that removing the dependency might reduce some of our woes.

I'm also hopeful that we can build the ip-reconciler controller as a kind of model that we can use as a reference when working through a controller for the Multus dynamic attachments controller.

However, if it's not practical, all bets are off -- I'm ok to double down on using it.

[s1061123]

I'm second on that. Less dependency library improves maintenability, such as update vendor. So if possible, I prefer to remove controller-runtime.

[maiqueb]

Implemented in #225 .

[maiqueb]

... which was merged.