Add german translation guidelines (#14283)

* Add german translation guidelines

* Add German Language to Docs

* add Translation cateory & move guidelines into it

Co-authored-by: kolaente <k@knt.li>
Co-authored-by: 6543 <6543@obermui.de>

docs/content/page/index.de-de.md

@@ -0,0 +1,36 @@
+---
+date: "2016-11-08T16:00:00+02:00"
+title: "Dokumentation"
+slug: "documentation"
+url: "/de-de/"
+weight: 10
+toc: false
+draft: false
+---
+
+# Was ist Gitea?
+
+Gitea ist ein einfacher, selbst gehosteter Git-Service. Änlich wie GitHub, Bitbucket oder GitLab.  
+Gitea ist ein [Gogs](http://gogs.io)-Fork.
+
+## Ziele
+
+ * Einfach zu installieren
+ * Plattformübergreifend
+ * Leichtgewichtig
+ * Quelloffen
+
+## System Voraussetzungen
+
+- A Raspberry Pi 3 is powerful enough to run Gitea for small workloads.
+- 2 CPU cores and 1GB RAM is typically sufficient for small teams/projects.
+- Gitea should be run with a dedicated non-root system account on UNIX-type systems.
+   - Note: Gitea manages the `~/.ssh/authorized_keys` file. Running Gitea as a regular user could break that user's ability to log in.
+- [Git](https://git-scm.com/) version 1.7.2 or later is required. Version 1.9.0 or later is recommended. Also please note:
+   - Git [large file storage](https://git-lfs.github.com/) will be available if enabled when git >= 2.1.2.
+   - Git commit-graph rendering will be enabled automatically when git >= 2.18.
+
+## Browser Unterstützung
+
+- Letzten 2 Versions von Chrome, Firefox, Safari, Edge (EdgeHTML) and Edge (Chromium)
+- Firefox ESR