cmdeploy: add ssh_host chatmail.ini option to deploy remotely

chatmaild/src/chatmaild/config.py

@@ -18,6 +18,7 @@ class Config:
         self._inipath = inipath
         raw_domain = params["mail_domain"]
         self.mail_domain_bare = raw_domain
+        self.ssh_host = params.get("ssh_host", raw_domain)
 
         if is_valid_ipv4(raw_domain):
             self.ipv4_relay = raw_domain

chatmaild/src/chatmaild/ini/chatmail.ini.f

@@ -3,6 +3,9 @@
 # mail domain (MUST be set to fully qualified chat mail domain)
 mail_domain = {mail_domain}
 
+# Where to deploy the relay - if unspecified, mail_domain will be used.
+ssh_host = localhost
+
 #
 # If you only do private test deploys, you don't need to modify any settings below
 #