Adding a function to create a cluster from manager

[guilhem]

I see many providers creating a cluster.Cluster with New without any options.

That could be a problem for caching, scheme, etc.

Controller runtime pass options from the manager to the cluster creation:
https://github.com/kubernetes-sigs/controller-runtime/blob/2053ba3d414e7cf9b47ae407e5c860556b3113b0/pkg/manager/manager.go#L352-L360

Could we integrate a little deeper with the manager?

I propose this interface #131 that could help
But maybe there are better ideas