Updates to Qt6.6 and various misc fixes for window and macOS

This will currently not build on Ubuntu 22 or 23.04 because of unavailability of Qt6.6

a patch for building it with Qt 6.3 will be added in a followup MR

This fixes #748 (closed) #744 (closed) #765 (closed)

Since the changes in this MR are not intended to alter behavior of the app, testing should make sure that it is working exactly like before

Note: I've found using aqt to install Qt6.6 to be the easiest