Improve ssh config definition

defaults/main.yml

+tunnel_user_name: 'systunnel'

templates/ssh_config

 # See all parameters at http://www.openbsd.org/cgi-bin/man.cgi?query=ssh_config
 
 StrictHostKeyChecking no
-ForwardAgent yes
+ForwardAgent no
 
 {% for host in commonauth_extras|default([]) %}
-{% if host.certfile is defined %}
+{% if host.ssh is defined %}
 {% for name in host.names %}
 Host {{ name }}
-  IdentityFile ~/.ssh/{{ host.certfile }}
+{% for key, value in host.ssh.iteritems() %}
+  {{ key }} {{ value }}
+{% endfor %}
 
 {% endfor %}
 {% endif %}