Merge branch 'dev' into 'master'

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

See merge request bohacfr2/apo-sem!1

Merge branch 'docs' into 'dev'

Add final documenttion

See merge request bohacfr2/apo-sem!2

docs: add final text viewer and file browser diagrams

docs: add block diagrams for image viewer and text viewer