[bitnami/rabbitmq-cluster-operator] Add AdmissionWebhookConfig toggle

[silveiralexf]

Description of the change

This PR proposes a new toggle to allow users to skip creation of AdmissionWebhookConfig resource.

Benefits

This toggle can be useful for when users have restricted cluster-wide permissions and are only allowed to deploy namespaced scope resources.

Possible drawbacks

The only drawback is the fact that users would have to manually create the AdmissionWebhookConfig by themselves.

Applicable issues

• N/A

Additional information

Since the default value for the toggle is set to false we would keep compatibility with the current behaviour, without risking a breaking change for users that are unaware or don't require the use of this toggle -- only users who explicitly opt-in would make use of it.

Checklist

• Chart version bumped in Chart.yaml according to semver. This is not necessary when the changes only affect README.md files.
• Variables are documented in the values.yaml and added to the README.md using readme-generator-for-helm
• Title of the pull request follows this pattern [bitnami/<name_of_the_chart>] Descriptive title
• All commits signed off and in agreement of Developer Certificate of Origin (DCO)

[fmulero]

Thanks a lot @silveiralexf for your contribution.

LGTM