. move the setting of the xterm title to site_config::shell

 . change the xterm file resource to use standard source lines, switch to single
 quotes, quote mode, and line up parameters

 . move the mosh pieces into a site_ssh::mosh class and only include it if the
 right mosh variable is enabled, passing into the class the necessary hiera parameters

 . lint the site_ssh::mosh resources

 . change the authorized_keys class to accept the key parameter which is passed
 in from the main ssh class (but allow for out of scope variable lookup when the
 tag is passed)

Change-Id: Ieec5a3932de9bad1b98633032b28f88e91e46604

to do tor lookups over DNS on servers, if tor services are defined.

To do this, we remove the bind9 configurations from site_config::resolvconf.pp
and replace it with site_config::caching_resolver with a basic unbound
configuration that can be used everywhere. The unbound configuration enables a
/etc/unbound/conf.d directory for additional config snippits that can be dropped
in from other places. This will be used for setting up different interfaces in
the vpn gateway, for example.

There will be a set of transition package/file absent blocks to clean up
providers.