feature: set interface for keepalived

[ghormoon]

Summary

it would be nice to be able to set which interface to use for keepalived.
if you have a host with multiple interfaces (e.g. one with access to internet, second one for internal communication on private IPs), there's currently no way to use other than the public internet one for keepalived communication, as it will pick the one with default route instead of picking the one that matches api ip subnet (or an option to pick which one to use)

another nice thing would be to be able to set pass and router id, so potentially multiple clusters can reside on the same network subnet.

I might have a look to make a PR for it, if nobody won't be faster

Issue Type

Feature Idea

[ghormoon]

i've stumbled upon rke2_bind_address and rke2_interface which would make sense to utilise there, if set.