Merge branch 'dev' into 'master'

Implement first versions of file browser, text viewer and image viewer

See merge request bohacfr2/apo-sem!1

refactor: split filebrowser main to more functions

fix: set rgb leds to lower brightness

feat: add keyboard filter 0 for any key

feat: implement basic directory browser window

feat: add commands save and restore states

refactor: commands size and count types

feat: add mzapo sdl

fix: text viewer blink rgb leds when scroll past line

fix: rgb leds time difference

feat: add timeout for rgb leds

refactor: remove unnecessary libraries linked

refactor: cleanup build flags

docs: correct formatting

docs: add code documentation

refactor: move gui elements to gui library

fix: comands uninitialised memory access

feat: add base gui functions

refactor: move direction to library

refactor: put all pheripherals to one object