docs/book: Update quick start guide for CAPA with cert-manager changes

[wfernandes]

What steps did you take and what happened:
[A clear and concise description on how to REPRODUCE the bug.]
I followed the quickstart instructions for deploying CAPA and noticed that the CAPA controller manager wasn't starting up.

What did you expect to happen:
Expected everything to either work as before or documentation indicating what steps need to be taken to get a quick start state.

Anything else you would like to add:
These are the events when I ran kubectl describe pod -l control-plane=capa-controller-manager -n capa-system

  Warning  FailedMount       69s                    kubelet, wff-oct15-control-plane  Unable to mount volumes for pod "capa-controller-manager-66b7cd9cbc-kcrqx_capa-system(32e24cf0-fc6f-4dcc-a79d-11ca3896bab8)": timeout expired waiting for volumes to attach or mount for pod "capa-system"/"capa-controller-manager-66b7cd9cbc-kcrqx". list of unmounted volumes=[cert]. list of unattached volumes=[cert credentials default-token-qxv8m]
  Warning  FailedMount       64s (x9 over 3m11s)    kubelet, wff-oct15-control-plane  MountVolume.SetUp failed for volume "cert" : secret "webhook-server-cert" not found

/kind documentation

[noamran]

/assign