[MAGEMEP-147] Update css for add attribute dialog

Make dialog look bigger and fitted inside current dimensions.
[MAGEMEP-147] Update chosen js library

Update library and html code accordingly to keep current functionality.
[MAGEMEP-147] Add support for translation in MEP

Add translation files and update configuration accordingly. Javascript translation
configuration were also added.
[MAGEMEP-147] Update translation file and fix css selectors for attr select dialog