re-add slide pages

docs/slides.md

docs/unterweisung-allgemeine.md

docs/unterweisung-digitallabor.md

docs/unterweisung-fdm.md

docs/unterweisung-laser.md

docs/unterweisung-shaper.md

docs/ws-3d-scan.md

docs/ws-luftdaten.md

docs/ws-microcontroller.md

public/digitallabor/index.html

public/en/slides/index.html

public/en/unterweisung-allgemeine/index.html

public/en/unterweisung-digitallabor/index.html

public/en/unterweisung-fdm/index.html

public/en/unterweisung-laser/index.html

public/en/unterweisung-shaper/index.html

public/en/ws-3d-scan/index.html

public/en/ws-luftdaten/index.html

public/en/ws-microcontroller/index.html

public/feed_rss_created.xml