Added Spanish Translation

[LoveAndCoding]

Added the Spanish translation done by Lenin Peña. Credited in the README.

[JeffryBooher]

@ktsashes thanks for translating MuCow documentation. It looks like we now have new content to translate so can you take a look and translate the new content so we have a consistent level of information across the locales?

[LoveAndCoding]

The Spanish translation was done by @leninalbertolp so you might want to see if they would be willing to update it. My Spanish is rusty (at best)

[JeffryBooher]

He has a pull request to translate to Spanish but it has merge conflicts so I thought your translation was a better start. I'm not even sure what we do with the translations yet. I'm working with @Caussen to figure that out.

[LoveAndCoding]

Well @clabland should have thoughts because we talked about it before. My original thought was to put it into separate sub-folders to keep things clean, and have the web UI have some way to switch between.

My translation is merely a copy of the other one, but put into a folder to avoid conflicts and overrides. The web version of the translation needs strategy though.