Attach GUI through LVGL

[gabordemooij]

Purpose of this issue is to make it so that:

• User can make GUI using EEZ Studio https://www.envox.eu/studio/studio-introduction/ or LVGL UI Editor https://forum.lvgl.io/t/introducing-lvgls-ui-editor-preview-of-v0-1/19280
• Or... user can simply grab a prefab template GUI
• User converts GUI via adapter to .so/.dll/.dylib
• User loads GUI through Media link:... or imports it through Plugin loader (have to decide)
• User manipulates GUI through 'unknown' messages i.e. GUI blah: 1 = send blah = 1 to GUI etc...
• User receives events from GUI as 'unknown' messages and can attach tasks to implement handlers

GUI is build using:

• https://wiki.libsdl.org/SDL2/FrontPage
• https://lvgl.io/