Add haproxy helper scripts
    
    - check_haproxy_config runs haproxy -c -f
    - grep_haproxy_config greps haproxy.cfg for section headers and the
      given needle
    
    Both scripts get installed to /usr/local/bin/ and symlinked to
    /etc/haproxy/
    
    Also move profile/proxy.sls to profile/proxy/init.sls and include
    the new profile.proxy.haproxy-scripts in it.