Add translation for Spanish

[dattaz]

We want to have our interface for gutenberg project in Spanish. File with strings to translate in json is here https://github.com/openzim/gutenberg/blob/master/gutenbergtozim/l10n.py and you should add you locale here : https://github.com/openzim/gutenberg/blob/master/gutenbergtozim/export.py#L40

[ghost]

I could pick up this one!

[kelson42]

@chocomochi thx

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be now be reviewed manually. Thank you for your contributions.

[ghost]

I could help, but never have contributed to opensource so I will need some guidance :D

[ghost]

I've just looked at both files and they look like they are done. I think the issue can be closed.

[rgaudin]

Thank you