add uidmap in order to use rootless docker

Found out there's a rootless way of running docker, but we're missing uidmap and maybe iptables.

https://docs.docker.com/engine/security/rootless/

manifests/server.pp

@@ -110,6 +110,7 @@ class debian::server {
       'irssi',
       'firefox-esr',
       'micro',
+      'uidmap',
     ]:
       ensure => installed,
   }