Add guest capabilities file for Rocky Linux

[evenreven]

Thanks for creating this great plugin!

This PR adds guest capabilities file for Rocky Linux 8. It's basically a copy/paste job from the :centos_8 part of the centos capabilities, but with the 6 and 7 case/when statement removed since it doesn't apply to Rocky (which launched with version 8).

Let me know if this lacks something or is incomplete in some way.

---

My setup (if it's relevant):

Since vagrant-libvirt doesn't work with the upstream package on Fedora 35 (and the Fedora-provided package is 2.2.16 (which doesn't support Rocky guests)), I built a Vagrant Podman container like this:

#!/bin/bash -x
container=$(buildah from "fedora:rawhide")
buildah run "$container" -- dnf install -y openssh-server openssh-clients vagrant vagrant-libvirt
buildah run "$container" -- dnf clean all
buildah commit "$container" "vagrant"

Then after executing this, I run the container:

podman run --rm -it \
  --volume /run/libvirt:/run/ \ 
  --volume "${HOME}:${HOME}:rslave" \ 
  -v $SSH_AUTH_SOCK:$SSH_AUTH_SOCK \ 
  -e SSH_AUTH_SOCK=$SSH_AUTH_SOCK \
  --env "HOME=${HOME}" \
  --workdir "$(pwd)" \
  --net host \
  --privileged \
  --security-opt label=disable \ 
  localhost/vagrant:latest

Then I installed my locally built gem inside the container with vagrant plugin install ./vagrant-sshfs-1.3.6.gem.

Relevant part of my Vagrantfile:

Vagrant.configure("2") do |config|
  config.vm.box = "generic/rocky8"
  config.vm.network :forwarded_port, guest: 3000, host: 3000
  config.vm.network :private_network, type: "dhcp"
  config.ssh.forward_agent = true
  config.vm.synced_folder ".", "/vagrant", type: "sshfs"
  config.vm.provider :libvirt do |lv|
    lv.qemu_use_session = false
  end
end

[tuupola]

Ping @dustymabe

[tuupola]

Ping @dustymabe

[dustymabe]

Thanks. I'll merge this and perform any fixups later.

Note, though that right now there is an issue with the Rocky guest detection in Vagrant because Rocky still ships the centos-release file. So it will erroneously get picked up as Centos. More details in one of the commits in this PR: hashicorp/vagrant#12785