[ci skip] UX guide: clean up term tables in copy

[ci skip] UX guide: update dropdown max height for multiline items

Describe hover, focus and active states for primary and secondary
buttons.

Organized the icons section in a table. Replaced images for icons
so they are all the same size.

Organized the color section in a table. Replaced the images with
new ones so the table would have a more manageable size. Updated
the values for some colors to show the $color-light shade.

Remove commented sections

Remove `db/schema.rb`

Add db/schema.rb from origin/master

Fix typos

Primary and secondary links should be dark blue on hover

Update anchor image to dark blue for secondary

Clean up markdown

Fix anchorlinks image

Fix spelling

[ci skip]

Block out pages needed for ux_guide

Add resources stub to ux_guide home

Fill out principles and basics

Add TOC to basics

Move all of UI guide to new UX guide structure

Add first level structure on ux-guide pages

Add more details to buttons

Add button images. Update link on development

Renamed surfaces to templates. Add tooltip details

Update typography and icons on Basics page

Add images for color. First draft of voice and tone

Delete findings page

Refine pages. Fill out Surfaces pages

Clean up layout on basics, surfaces, features. Add anchorlinks and counts to components

Fill out components page

Add item title and system info block

Fill out Features page

Switch tooltip placement image