GSoC: Move the gallery code to use ZIP files Id

[Ilmari Lauhakangas]

Ahmad Ganzouri kirjoitti 16.2.2020 klo 10.57:
> I want to join GSoC'20. I've already tried to solve easy hacks and 
> submit patch
> https://gerrit.libreoffice.org/c/core/+/87372
> 
> Can you please tell me where to start or assign me a task?

Google will announce the selected organisations on 20 Feb.

While waiting, it is always a good idea to solve easy hacks with the 
keyword difficultyInteresting. Writing beautiful solutions to these will 
make a good impression on mentors.

Ilmari