Add openrc support to k3s_server role

[dereknola]

Changes

• Supports openrc init systems for k3s_server (k3s_agent and k3s_upgrade support was completed in prior PRs)
• Simplify service start, make it all restarted which is guaranteed to bounce/start the service (covering both first start and restart cases)
• Fix issue introduced with 65a3b5f6ace6d5cf4e88c2c0424ee970820faf47m were extra_server_args were not being passed to the install script
• Added full openrc testing (previously split between systemd servers and openrc agents)

Linked Issues

#463