improve language in German version

guide/de/dect-phones.adoc

guide/de/intro.adoc

guide/de/pack-list.adoc

guide/de/quickstart.adoc

guide/de/radio.adoc

guide/de/teams.adoc

guide/de/teams/awareness-team.adoc

guide/de/teams/bottles-team.adoc

guide/de/teams/cert.adoc

guide/de/teams/gelb-team.adoc

guide/de/teams/hac.adoc

guide/de/teams/heaven.adoc

guide/de/teams/infodesk.adoc

guide/de/teams/loc.adoc

guide/de/teams/poc.adoc

guide/de/teams/security.adoc

guide/de/teams/voc.adoc

guide/de/what-is-an-angel.adoc

guide/de/what-is-congress.adoc

guide/de/what-is-heaven.adoc