Added translations

Hello @justinfreeman, I made some changes to translate the interface and I have also implemented two new languages Spanish and Catalan. I think that by publishing the extension, everything can be translated. What do you think? If you have any suggestions, please let me know.

I haven't tested the strings with the Dutch language, maybe there is something missing because of not having all the variables like the English language, I haven't implemented it because I don't know the language, but you can also put it in English if necessary.

issue: #12 (closed)

Thanks!