Add Arch Linux support

[Javex]

Add new vars/Archlinux.yml which lists the two equivalent packages to the ones installed for Debian.yml already.

I've tested it locally (hopefully correctly). Not sure if you intend to support Arch at all given the comment in the readme, but I thought I'd try.

Thanks for making this role available :-)

[Javex]

Any chance I could get this PR merged? :-)