[Tails-l10n] (review)[de] wiki/src/doc/first_steps/installat…

Hi,

I translated the following two pages (they belong together, so I only
created one branch. If that's a problem ping me) :

https://gitlab.com/spriver/tails.git
branch: de_manual_installation

wiki/src/doc/first_steps/installation/manual.de.po
commit: 8c7c3705 Initial translation

wiki/src/doc/first_steps/installation/manual.intro.de.po
commit: 1faf6efc Initial translation



Cheers!

spriver