This PR is related to #1244 and #1586 and adds support for macOS and potentially Windows (untested, see below) by using a platform independent library (https://github.com/libusb/hidapi) for device access. Solaar will be able to pair and configure devices but the rule and diversion system will not work because it is Linux specific and not really portable.
macOS
For macOS all dependencies can be installed via homebrew: brew install hidapi gtk+3 pygobject3
Windows
This PR should also support Windows without any further changes but I don't have the environment to test this. If someone wants to give this a try the first step would be to obtain the hdiapi DLL from https://github.com/libusb/hidapi/releases and check that the command line interface works.
Getting the GUI to work requires GTK which seems non-trivial to install on windows. The starting point for this would be https://pygobject.readthedocs.io/en/latest/getting_started.html#windows-getting-started