Update Qt demo applications for new app framework

Issue to track updating some of the Qt demo applications to work without the old application framework and with the new one for Marlin M1:

• hvac
• dashboard
• ondemandnavi
• settings

This also will include some rework of the libqtappfw library that these applications use to abstract use of the application framework APIs, as stubbing out / reworking things in it is lower effort than reworking the applications in places.

Note that there will be some loss of functionality wrt the full demo setup since there is nothing to replace the CAN/LIN support from the CAN and signal composer bindings at present.