Mms: Update German translation

Patch Set 1:    * add translation for 'Option to strip
                  all unicode characters from SMS'

Patch Set 2:    * rename string after comments

Patch Set 3-5:  * rebase

Patch Set 6:    * add translation for 'Insert contact info'
                * unify translations

Change-Id: Iace6ae5e75d0d23510252188b568245a60ec185d