Fix snapshots on repos with special characters in the name/directory

The prefix parameter needed to be quoted to ensure the archive command went through successfully
Fixed: No owner specified notices

When no owner is specified in the line, PHP will return a notice that it cannot read $regs[2] (it does not exist).
It is not a critical bug, but it is very annoying.

I fixed this behavior by first checking if $regs[2] isset.
Update german translations

squashed xiphux commit of :
c72cb49d386ed319db71457d0c8ade32782cc81f
38b7ee104dac8f3e339f7920eed084f24632b9da
091b6e06fe80a56dc22cf8b73fad8f7f5688c8d7

make more sense.