Converted views grid style plugin to use divs instead of a table

The views grid style plugin in Drupal 8 now uses <div/> markup instead of <table/>. This change was loosely based off of the Views Responsive Grid module.

Markup

The template markup can be found at: views-view-grid.html.twig

Style options removed:

• Fill Single Line
• Summary

Style options added:

• Automatic width - The width of each column will be calculated automatically based on the number of columns provided. If additional classes are entered or a theme injects classes based on a grid system, disabling this option may prove beneficial.
• Custom row classes - Additional classes to provide on each row.
• Default row classes - Adds the default views row classes like views-row, row-1 and clearfix to the output.
• Custom column classes - Additional classes to provide on each column.
• Default column classes - Add the default views column classes like views-col, col-1 and clearfix to the output.

Styling Example

An example can be found at: #2031447: Add new views-grid styling to Bartik