Consider if to align manager flag names with upstream Kubernetes components

[fabriziopandini]

While working on adding support for Prometheus in CAPI TiltFile we noticed that latest CAPDO is still using old flags name for metrics and leader election (see
https://cluster-api.sigs.k8s.io/developer/providers/v0.3-to-v0.4.html#align-manager-flag-names-with-upstream-kubernetes-components).

Even this is not mandatory, I suggest the CAPDO team to consider aligning flag names for sake of consistency across providers; also deploying Prometheus in local dev env using the CAPI Tiltfile won't work without this change as well as "--metrics-bind-addr=127.0.0.1:8080" in your manager.yaml file suggested in the same doc linked above.

[cpanato]

oh! I thought I change that in the v1beta upgrade, I will fix that @fabriziopandini it is my fault

/assign