[Feature] Built-in dictionary + redesign

Hi @vitonsky and contributors,

As the title says, a built-in dictionary that gives word definition, synonyms,... For the sources, I personally use TheFreeDictionary and Wiktionary for my definitions as they are the easiest to use and accurate. But I don't know if they can get implemented or if they have a free API.

I made quick mockups of the dictionary feature + redesigned the translation pop-up to give ideas.

How would it work ?

If one word is selected on a page = translation + dictionary pop-up shows up If a few words/sentence selected = only translation pop-up shows up

Translation pop-up redesign :

Single word translation + dictionary :