D-Rats repeater defaults to valid well known call sign

[wb8tyw]

The D-Rats repeater configuration defaults to a well known default call sign instead of a placeholder.

The default should be an obviously invalid call sign and the repeater functionality should be disabled, except for possibly localhost until the configuration is changed.

[wb8tyw]

I am also not sure what the D-Rats repeater call sign is actually used for.

As near as I can tell, it is not used internet conections.

I am not sure it is in the authentication dialog, or if there is any way for a client to query the repeater.

It may be used on other transports, which only exist and have not really been tested in the 0.4 version of D-Rats.