(manifests/v2) add support for webhooks by default and docs

[estroz]

Description of the change:

• internal/plugins/manifests/v2: initialize project with a config/manifests/kustomization.yaml that contains a patch to remove the cert volume and mount from the default manager configuration.
• internal/cmd/operator-sdk/generate/kustomize: use the manifests/v2 kustomization.yaml for backwards-compatibility.

Motivation for the change: no kustomize helpers are created to enable webhooks by default. This is considered a bug since the CSV generator supports webhooks (see #4244).

Closes #4240
Closes #4244
Closes #4439

/kind bug

Checklist

If the pull request includes user-facing changes, extra documentation is required:

• Add a new changelog fragment in changelog/fragments (see changelog/fragments/00-template.yaml)
• Add or update relevant sections of the docs website in website/content/en/docs

[estroz]

Still need to update docs and add a changelog

[camilamacedo86]

IMO we are just missing some nits to get this merged:

• We need to provide the changelog which also will be useful for those who face this problem.
• Would be nice to add the manual steps to fix that in the FAQ as well. Do we have them already?

[camilamacedo86]

/lgtm
/approved

[camilamacedo86]

/hold

It is true. It is missing the changelog and docs.

[jmrodri]

/lgtm

[openshift-ci-robot]

New changes are detected. LGTM label has been removed.

[estroz]

/hold cancel