Without this a build failure would occur for those that are not using the languages.js file.
e.g.,
```
sitemap.js triggered...
module.js:471
throw err;
^
Error: Cannot find module '/home/ubuntu/fasttext-website/website/languages.js'
at Function.Module._resolveFilename (module.js:469:15)
at Function.Module._load (module.js:417:25)
at Module.require (module.js:497:17)
at require (internal/module.js:20:19)
at module.exports (/home/ubuntu/fasttext-website/website/node_modules/docusaurus/lib/server/sitemap.js:48:15)
at execute (/home/ubuntu/fasttext-website/website/node_modules/docusaurus/lib/server/generate.js:316:5)
at Object.<anonymous> (/home/ubuntu/fasttext-website/website/node_modules/docusaurus/lib/build-files.js:31:1)
at Module._compile (module.js:570:32)
at Object.Module._extensions..js (module.js:579:10)
at Module.load (module.js:487:32)
Error: generating html failed
```
* added a note about needing more than one language to be enabled to allow for a drop down
* Removing debug statements
* Add 'Help Translate' to translatable strings, improves error messages around missing translated strings, calls write-translations on some routes
* Adds sitemap.xml to live server and build. Versioning not supported. -- Also did some file name and module cache cleanups.
