fix(Traefik Proxy)!: use namespaceOverride as expected

[mloiseleur]

What does this PR do?

Use namespaceOverride in

• publishedService of ingress
• status address of gateway
• antiaffinity example
• certificate generation for Traefik Hub mutating webhook
• name of ClusterRole
• label selector (matchLabel of Deployment/StatefulSet)

⚠️ When using namespaceOverride, the label selector will be changed. It's an immutable field. It means it will delete and recreate the Deployment or the StatefulSet. It will delete all the pods before creating new ones.

=> When upgrading, it's recommended to deploy a new instance with the new version, switch the traffic to it and delete the previous one.

Motivation

Fixes #1289 (and similar issues)

More

• Yes, I updated the tests accordingly
• Yes, I updated the schema accordingly
• Yes, I ran make test and all the tests passed

[darkweaver87]

IMO 5 references to .Release.Namespace should be removed in traefik/templates/_helpers.tpl in the context of this PR.
It will:

• fix hub admission webhook
• fix cluster role name

[darkweaver87]

LGTM