Remove stalte posts

content/posts/de/Workday_dec19.md

content/posts/de/boltenheide-foss-pilotschule.md

content/posts/de/clt-2019.md

content/posts/de/dienstausfall-2019.md

content/posts/de/froglabs_froscon_2019.md

content/posts/de/glt-2019.md

content/posts/de/hacknfun.md

content/posts/de/skolelinux-sprint-19.md

content/posts/de/tuebix-2019.md

content/posts/en/Workday_dec19.md

content/posts/en/boltenheide-foss-pilotschule.md

content/posts/en/clt-2019.md

content/posts/en/dienstausfall-2019.md

content/posts/en/froglabs_froscon_2019.md

content/posts/en/glt-2019.md

content/posts/en/hacknfun.md

content/posts/en/skolelinux-sprint-19.md

content/posts/en/tuebix-2019.md