Improve Component List Form UI

Problem/Motivation

The current component selection form is a simple list of icons+label. This works well but could be more visually appealing. In addition, the search input lacks common classes that allow admin theme's to style inputs consistently.

Proposed resolution

Adjust styling for the component list form to display paragraph types in a grid, enlarge the icons, and add common form input classes to the search input. Doing this has an added benefit of making the form easier to use for touch devices due to the large hit area for each option.

User interface changes

See attach screenshot

API changes

None.

Data model changes

None.