Add cleaned ru_RU translation

* Remove wrong german translation

* Clean up vanished strings

Author: ann0see

Jamulus.pro

@@ -64,7 +64,8 @@ TRANSLATIONS = src/translation/translation_de_DE.ts \
     src/translation/translation_sk_SK.ts \
     src/translation/translation_it_IT.ts \
     src/translation/translation_sv_SE.ts \
-    src/translation/translation_zh_CN.ts
+    src/translation/translation_zh_CN.ts \
+    src/translation/translation_ru_RU.ts
 
 INCLUDEPATH += src