Use 3rd Party Library for User Agent Detection

From  @oleksandr-danylchenko: 

> Maybe we can use a 3rd party library like https://www.npmjs.com/package/ua-parser-js? It's constantly maintained and will account for any future UA string shenanigans.

https://github.com/recogito/text-annotator-js/pull/151#pullrequestreview-2345288809