Merge branch 'dev' into 'master'

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

See merge request bohacfr2/apo-sem!1

feat: add outline for cursor

feat: add zooming to cursor

fix: movement within border underflow of unsigned integer

fix: cursor render coordinates

refactor: unify cursor functions

fix: add missing include guards

fix: struct constants

feat: add cursor functions