[Feature request] Add Printers by domain name

Feature request to add printer moonraker instances by domain name useful for setups with multiple printers using reverse proxy and for setups with dhcp based domain registration. Ideally should support all or as many as possible of:

* FQDN - **printer1.example.com**
* mDNS - **printer1**
* default DHCP search domain - **printer1** where printer1 is short name to printer1.us.example.com (us.example.com search domain)

No files, tests, or entry points are named. Start by locating the existing printer or Moonraker connection configuration, then check how host names are resolved and how connection success is verified. Done means supporting the requested FQDN, mDNS, and DHCP search-domain cases, or documenting which cases are supported.

Written by the indexing model from the issue text.