Remove ingress controller posthook

[janosSarusiKis]

Q	A
Bug fix?	no
New feature?	no
API breaks?	no
Deprecations?	no
Related tickets	#3444
License	Apache 2.0

What's in this PR?

• Removed IngressControllerPostHook
• Added InstallIngressControllerActivity to cluster setup workflow

Why?

To be able to deprecate post hook functionality.

Checklist

• Implementation tested (with at least one cloud provider)
• Code meets the Developer Guide

[pregnor]

Question: is there a reason we use a different nomenclature for this activity compared to the similar cluster autoscaler one (install here versus deploy at the CA)? If these activities do the same, I as a reader would intuitively expect them to be called similarly for clarity purposes.
Whichever fits the case better is up for consideration.

(If we decide to rename, don't forget to rename both the file and the code references including the activity name.)

[pregnor]

Oh I see there are divergences already, because NPLS is also called install while the cluster autoscaler is called deploy, so this kind of invalidates my comment for now (consolidating these is going to be a bigger refactor because the divergence is not being introduced here which I originally assumed).

You can skip this thread.

(Not resolving the thread for visibility purposes.)

[janosSarusiKis]

I will rename it to deploy, since autoscaler is newer and you too preferred that name.

[pregnor]

I think it is debatable, because in Helm terminology we are installing releases and not deploying something, but I'm fine with either names for now as there is going to be at least one outlier.

[pregnor]

Well I definitely didn't expect this much hassle for the provider information, but that's the easiest way to propagate, then it's fine.