feat(docs/from sources): Debian 8 → 9 (#3978)
feat(docs/from sources): Debian 8 → 9 (#3978)

* update cloud init docu

* update cloudinit images

* fix png links

* add emergency shutdown feature doc

* fix emergency shutdown typo

* Update to Debian 9 recommendation

vatesfr/xo-web,lmcro/xo-web,vatesfr/xo-web,lmcro/xo-web,lmcro/xo-web