fix: 监控时增加只读模式参数, 提升安全性 (#290)

看参考 https://guacamole.apache.org/doc/gug/configuring-guacamole.html
read-only参数

server/common/guacamole/guacd.go

@@ -52,6 +52,7 @@ const (
 	SwapRedBlue = "swap-red-blue"
 	DestHost    = "dest-host"
 	DestPort    = "dest-port"
+	ReadOnly    = "read-only"
 
 	UsernameRegex     = "username-regex"
 	PasswordRegex     = "password-regex"
@@ -83,6 +84,10 @@ func NewConfiguration() (config *Configuration) {
 	return config
 }
 
+func (opt *Configuration) SetReadOnlyMode() {
+	opt.Parameters[ReadOnly] = "true"
+}
+
 func (opt *Configuration) SetParameter(name, value string) {
 	opt.Parameters[name] = value
 }