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 imageviewer to more functions and files

feat: add image viewer mode indicator

feat: add correct error messages for text viewer and image viewer

refactor: delete unused code

feat: add mzapo sdl

refactor: use libmagic even for ppm

refactor: use libmagic instead of custom handling magic numbers

refactor: remove irrelevant comment

refactor: move direction to library

feat: add outline for cursor

refactor: add errors to enum

feat: turn on red led on error

feat: turn on ledstrip for cursor position

feat: add loading progress bar

refactor: split pheripherals to separate library

feat: add jpeg and png load

feat: add mode change to scroll through picture

fix: close program after not loading image

feat: make rotation encoders more natural by changing direction