[chart/redis-ha] allow headless haproxy service

[dani-CO-CN]

Is your feature request related to a problem? Please describe.
It is currently not possible to return the haproxy pods' IP addresses, you are forced to use the service IP.

Describe the solution you'd like
Allow setting the ClusterIP to None.

Describe alternatives you've considered
n/A

Additional context
Add any other context or screenshots about the feature request here.