linux: Add Write method to write characteristic value with response

[timklge]

Simple change that adds a Write (with response) method to the DeviceCharacteristic linux dbus implementation, consistent with what is already available in the windows and mac versions. It sets the dbus type argument of the WriteValue method, as listed in the documentation.

My use case is setting ble ftms simulation parameters, which requires writing with response to the ftms control characteristic. I verified that my ftms device successfully updates the parameters using the new Write method; it doesn't respond to WriteWithoutResponse on the characteristic in any way.

I have also set the type argument of WriteWithoutResponse to command, consistent with the suggestion by @tazjin in #382 .