Avoid importing upstream k8s packages

[Karthik-K-N]

This PR removes the dependency of upstream k8s. Because

We are planning to use this package across multiple repositories including cluster-api-provider-ibmcloud, if this repo has k8s dependency which makes the importer to be on the same k8s version.
This cannot be satisfied all the time as updating in this repo may cause issue in various repo's as well.

One of the reference to the error kubernetes-sigs/cluster-api-provider-ibmcloud#1608 (comment)

The removed function can be constructed again in the caller like

package main

import (
	"fmt"
	powerUtil "github.com/ppc64le-cloud/powervs-utils"
	"k8s.io/apimachinery/pkg/util/sets"
)

func main() {
	fmt.Println(AllKnownSysTypes())

}

// AllKnownSysTypes returns aggregated known system types from all regions.
func AllKnownSysTypes() sets.Set[string] {
	sysTypes := sets.New[string]()
	for _, region := range powerUtil.Regions {
		sysTypes.Insert(region.SysTypes...)
	}
	return sysTypes
}

[Karthik-K-N]

/cc @mkumatag @dharaneeshvrd @hamzy

[ppc64le-cloud-bot]

@Karthik-K-N: GitHub didn't allow me to request PR reviews from the following users: hamzy.

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/cc @mkumatag @dharaneeshvrd @hamzy

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[dharaneeshvrd]

/lgtm
/approve

[dharaneeshvrd]

@mkumatag Please approve this PR when you get a chance, need this dependancy for hypershift as well.

[mkumatag]

but the question is - is this consumed anywhere right now?

[Karthik-K-N]

I dont think its used any where @hamzy can confirm.

[hamzy]

I seemed to be the only person interested in having one place where all this code would be. There was no action done on my working solution.

[mkumatag]

yes, that's the reason we are removing the k8s.io deps so that we can import this code everywhere with no conflict with k8s deps

[mkumatag]

@hamzy if this function is not consumed anywhere, will merge this code and find some other way of implementing this function withought k8s sets package

[Karthik-K-N]

@mkumatag can this be merged?

[mkumatag]

/lgtm

[ppc64le-cloud-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dharaneeshvrd, Karthik-K-N, mkumatag

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