[ComamndPad] CommandPad and CompactCommandPad should have the option to select the system target

While using SkywardHub, it is common to forget changing the target systems in the Mavlink module before sending a message. This mistakes aren't easy to prevent in the OBSWs. The proper way should be improving the UI.

So, maybe a way to improve this part is to embed in the Command Pads the target system, instead of setting it in the serial mavlink module.