improvement(k8s): reduce dedicated CPUs for manager agent containers
improvement(k8s): reduce dedicated CPUs for manager agent containers

Now we provide 20% of a CPU core for each of the scylla manager agent
containers. It was needed before merge of the [1].
So, at first, we do not need such huge CPU dedication for it anymore.
And at second, running multi-tenant setup we get less CPUs for Scylla
containers which is undesired.

So, reduce it to be 4% which is completely enough after merge of the [1]

[1] https://github.com/scylladb/scylla-operator/pull/884

scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests