Adds support for gentoo and openrc, closing #37

[TheNightmanCodeth]

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[TheNightmanCodeth]

you know, I'm not 100% sure. However I do know that /etc/init.d/NetworkManager will be available on all systems with NetworkManager, whereas /etc/init.d/networking is not always available. If systemd systems can also call /etc/init.d/NetworkManager restart, then we could replace the whole conditional with that single statement. I also do know that all open-rc systems have rc-service, It's similar to service as in service restart ... on systemd systems

[TheNightmanCodeth]

Basically this PR, as-is simply adds gentoo, devuan, artix and other open-rc based distros to the list of compatible distros. Some people could have a wierd setup. And to be honest, if they do, they would be able to figure out how to submit their own PR adding their configuration 😆