[FEATURE] Add versionlock feature for RHEL-based distros

[mdschmitt]

Is your feature request related to a problem?

Not really, the functionality just exists for Debian-based systems, but not RHEL-based ones.

Describe the solution you'd like

If pin is set to true and the osfamily is RedHat, do a pkg.install yum-plugin-versionlock, then pkg.install salt with the appropriate version number, followed by cmd.run yum versionlock salt-minion (or master or whatever).

I think this could all go in salt/pin.sls.

Describe alternatives you've considered

N/A

Additional context

N/A