Update strings.xml

updated german language file
Updated Slovak translation
Updated Arabic translation
Move constants to app list adapter
Update LT
Server: move discussion forum
Added caching in privacy service, moved classes in privacy manager to separate files
Never expire privacy service caches
Use privacy service cache when memory class >= 64
Merge pull request #1136 from 28Black/patch-34

Updated German translation
Merge pull request #1137 from pylerSM/patch-16

Updated Slovak translation
Merge pull request #1138 from waleedhassan/patch-10

Updated Arabic translation
Merge pull request #1139 from smiledexter/patch-38

Updated Lithuanian translation
Updated changelog