Add Spanish translation

[nvdaes]

No description provided.

[nvdaes]

@danielweck : I have added the spanish translation as commented on email list.
Hope this helps. Thanks for your attention and work.

[panaC]

thank you very much for your PR.

Do you know how to connect the new language in the code ?
So that your PR can be integrated into thorium.

check this file : https://github.com/readium/readium-desktop/blob/develop/src/common/services/translator.ts

Otherwise we will integrate it

[nvdaes]

I modified the mentioned file. Please let me know if something needs to be added or changed. I suppose that locale-names files are automatically generated. Hope a procedure for contributing can be documented, maybe helpful :)

[nvdaes]

With my last commit, checks failed. Seems that src\resources\locale-names/esLang.json needs to be created to translate language names. In this case, I will push another commit for this, based on
http://utils.mucattu.com/iso_639-1.html
Please, let me know if this is not needed.

[panaC]

yes, you are right, @Scarsniik used this script to convert csv from wikipedia to json.
If that can help you. I guess these ISO codes are not easy to get.

[nvdaes]

I have followed the following criteria:

• Capitalize initial character of language names, as done in other languages, though in Spanish is only required in certain situations.
• Use the first or most wnown or easy name when various names can be used for the same language.
  Please, review and merge when appropiate. Thanks

[panaC]

perfect, thank-you. I tested it works well.

@danielweck will be able to merge if he agrees.

[nvdaes]

Thanks, if/when @danielweck merges this, I will make a post to share this with spanish users.

[danielweck]

Thank you! Merging this PR into a staging branch in order to check against the latest updates (keyboard shortcut editor new labels, etc.)

[danielweck]

Follow-up PR: #971