[META] Improve the style of the Rate widgets

Problem/Motivation

Styles have been copied from the Drupal 7 version. Some may be out of date or may need improvement.

Proposed resolution

#3069197: Improve the style of the "Number Up / Down" widget
#3069198: Improve the style of the "Thumbs Up" widget
#3069199: Improve the style of the "Thumbs Up / Down" widget
#3082504: Throbber icon shows up in the middle of Fivestar widget

Done:

#3069196: Improve the style of the "Fivestar" widget
#2880351: Add an active class on the active option for thumbs up/down
#3069200: Improve the style of the "Yes / No" widget

User interface changes

Possible small changes in the interface.