chore: add a vagrant config for testing

.gitignore

@@ -1 +1,2 @@
 /volumes
+.vagrant/

Vagrantfile

@@ -0,0 +1,14 @@
+Vagrant.configure("2") do |config|
+  # unnoficial RHEL images
+  (8..9).each do |n|
+    config.vm.define "rhel%d" % n do |vmconfig|
+      vmconfig.vm.box = "generic/rhel%d" % n
+    end
+  end
+  # allow ssh'ing with password authentication (username and password are "vagrant")
+  config.vm.provision "shell", inline: <<-EOF
+    sed -i 's/PasswordAuthentication no/PasswordAuthentication yes/g' /etc/ssh/sshd_config
+    # fallback to service for systems that don't use systemd
+    systemctl restart sshd.service
+  EOF
+end