Uicomponents

[cyclops1982]

This adds:

• a UIEntity base class
• 2 very basic uientity subclasses (UIBUtton and UISwitch)
• An observer/subject interface so that HAEntity can notify the UIentity of any updates
• Moves the client-lvgl to a list of button/switch controls in a flexbox
• removes the uithread_refresh stuff and move over to the observer pattern where needed
• cleans up some of the stuff we don't need anymore due to the above changes.

[Habbie]

tested all 3 frontends, merging!