No mass upload function of photos

[HtHNightwolf]

Expected Behavior

I can upload a group of photos.

Current Behavior

I can only upload one photo at a time.

Possible Solution

Implement the possibility to upload multiple photos.

Steps to Reproduce (for bugs)

1. Go to picture library
2. try to upload two or more photos at once

[M4LuZ]

This appears to be not that hard to implement and I've started implementation as part of #870.
In the meantime direct upload to webspace is possible
/Edit: Also if I interprete the code correctly it is also possible to upload a zip file and it will be auto-extracted at the destination