Tackle Operator must have OLM as requirement

[mrizzi]

The Prerequisites for Installing the Tackle Operator has just the cluster-admin role but it should mention also having OLM deployed in the Kubernetes instance otherwise the 1st command kubectl create -f https://operatorhub.io/install/tackle-operator.yaml will fail with something like

$ kubectl create -f https://operatorhub.io/install/tackle-operator.yaml
namespace/my-tackle-operator created
unable to recognize "https://operatorhub.io/install/tackle-operator.yaml": no matches for kind "OperatorGroup" in version "operators.coreos.com/v1"
unable to recognize "https://operatorhub.io/install/tackle-operator.yaml": no matches for kind "Subscription" in version "operators.coreos.com/v1alpha1"