Remove namespace on dnsProviderSecretRef to force same namespace as M…

[david-martin]

…anagedZone

Fixes #712

• Updated types
• Regenerated crd & bundle
• Updated example ManagedZones
• Added note to docs
• Updated tests

Locally the ManagedZone and dns Secret are in the same namespace:

kubectl get managedzone,secret -n multi-cluster-gateways
NAME                                     DOMAIN NAME      ID    RECORD COUNT   NAMESERVERS   READY
managedzone.kuadrant.io/mgc-dev-mz-aws   dm.hcpapps.net

NAME                         TYPE              DATA   AGE
secret/mgc-aws-credentials   kuadrant.io/aws   3      13m

[openshift-ci]

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[maleck13]

/lgtm