[Addon] VelaUX allow configuration of ingress class name

[oanasc]

The addon chart allows for gatewayDriver nginx or traefik and assumes that is going to be the name of the className, for nginx it then adds the annotation kubernetes.io/ingress.class. In a cluster with several ingress controllers however we need a way to set the value for the IngressClass name

[oanasc]

Attempted to update the addon definitions here, but it looks like a change to the addon definition is tied to a new image.