feat: added German translation (#172)

* Added German translation

About 96% of the plasmaoid into German. Missing strings for:

- AC online tag (as well as AC online)
- AC offline tag (as well as AC offline) (I think they are used for when you have a charging cable plugged into your laptop? I am on a desktop so I can't check)
- Quotes Monitor (as well as quotes – are they used for stocks?)
- User keys
- Has return

Also worth noting is that your redirection to stooq.com doesn't make sense for a German as it is a Polish stocks site

* Fixed some spelling issues

* fixed spelling of openSUSE

* Update de.po

Confused minimal with minimalistic. Changed translation accordingly

* added missing translation strings

Missing translations added for
- AC
- AC online (+tag)
- AC offline (+tag)
- Quotes (+Monitor)
- User keys
- has return
- Player data symbols

README.md

@@ -75,5 +75,5 @@ Links
 * [Scripts and bars](https://arcanis.me/en/2014/12/19/aw-v21-bells-and-whistles/)
 * Plasmoid on [kde-look](http://kde-look.org/content/show.php/Awesome+Widgets?content=157124)
 * DataEngine on [kde-look](http://kde-look.org/content/show.php/Extended+Systemmonitor+DataEngine?content=158773)
-* Archlinux [AUR](https://aur.archlinux.org/packages/plasma5-applet-awesome-widgets/) package
+* Archlinux [AUR](https://aur.archlinux.org/packages/plasma6-applets-awesome-widgets) package
 * [OpenSuse](http://software.opensuse.org/search?q=awesome-widgets) packages, [KF5 OpenSuse](http://software.opensuse.org/package/plasma5-awesome-widgets) package