frameworks/base: Update DE translation

Update custom_strings.xml

PS5 Put together:
PS4 from Ralph Meyer
https://gerrit.omnirom.org/#/c/4638/ from Robert Kornmesser
https://gerrit.omnirom.org/#/c/5223/ from Andreas B

PS7:
Removed some nbetwork "translatable="false"" strings
Added navbar-strings
Applyed some comments from PS5

Change-Id: Ic145f02b52f1d8a39b30ba8b8f6fc87f561e4e87
Merge "frameworks/base: Update DE translation" into android-4.4
frameworks/base: remove translatable=false

Change-Id: Ia46462a0fa2f30a299c59436b51d53cc7f0c8c15