Feature request: send command to HDMI switch

[VE3NEA]

When switching the mouse and keyboard between the screens, send a source selection command to the HDMI switch so that the monitor is switched as well. This will turn barrier from KM into a true KVM.

I am using barrier to switch the keyboard and mouse, and this HDMI switch to switch the monitor. All works fine, except that to switch the screens, I have to press both the barrier hotkey and the button on the switch.

It would be nice if the user could specify the RS232 port settings and the source switch command in the UI, and barrier would send this command to the specified COM port when switching the screens.

As a P.O.C., I have written code that sends the command to the switch on Windows, using my own
hard-coded port settings and commands. A complete solution will require some extra code to edit and store the settings.

[VE3NEA]

Here is the pull request for my P.O.C. code. It works fine on my system and could be used as part of the complete solution.

[github-actions]

This issue has been automatically marked as stale due to inactivity. It will be closed if no further activity occurs. Thank you for your contributions.

[shymega]

This is still being worked on. Adding bot mitigation label.