Add gpsd.allow_forms config option

For enabling use of GPSd with forms.

Ref la5nta#330

cfg/config.go

@@ -226,11 +226,15 @@ type GPSdConfig struct {
 	// expose your current position to anyone who has access to Pat!!!
 	EnableHTTP bool `json:"enable_http"`
 
-	// Use server time instead of timestamp provided by GPSd (e.g for older GPS
-	// device with week roll-over issue)
+	// Allow Winlink forms to use GPSd for aquiring your position.
+	//
+	// Caution: Your current GPS position will be automatically injected, without your explicit consent, into forms requesting such information.
+	AllowForms bool `json:"allow_forms"`
+
+	// Use server time instead of timestamp provided by GPSd (e.g for older GPS device with week roll-over issue).
 	UseServerTime bool `json:"use_server_time"`
 
-	// Address and port of GPSd server (e.g. localhost:2947)
+	// Address and port of GPSd server (e.g. localhost:2947).
 	Addr string `json:"addr"`
 }