add spanish translation

[kmomberg]

Let me know if there's any sentence that I need to try to shrink a little bit. I tagged it as Chilean Spanish, but I thinks it's neutral enough to be used as es_ES as well

[Lymphatus]

Thanks for the translation!
If you think it can be used and understood by (most) Spanish speakers, I would tag it as es_ES.

Also, I'm adding a few new strings in the last commits, so it's probably already outdated a little bit (sorry!). I'll stop adding new translation strings for a bit, so if you can update the file it would be awesome and I'll merge it right away.
Thanks again!

[kmomberg]

Changes done.
No worries if you need to add more strings. Translations shouldn't stop your work ;-)