[meta] Replace JQuery with vanilla Javascript in core

Problem/Motivation

Inspired by #3051352: [Plan] Remove unused jQuery UI components and replace with a suite of contrib packages for the continuous upgrade path

jQuery used to be so awesome and It has been with us since Drupal 5.0!
IE10 was released in 2012 and supported most (all?) of the vanilla javascript that is needed to replace jQuery code.

Using vanilla javascript would allow us to remove jQuery from Drupal core as a dependency.

Proposed resolution

http://vanilla-js.com :)

The web is full of great resources for making the switch:

• https://www.evermade.fi/replacing-jquery-native-javascript-projects/
• http://youmightnotneedjquery.com/
• https://www.previousnext.com.au/blog/removing-jquery-from-your-drupal-theme
• https://css-tricks.com/now-ever-might-not-need-jquery/

Remaining tasks