All components need a demo page

[beeman]

Issue

Not all the available components have a demo pages. There should be at least one demo for each of the components.

Some demos should be split up into multiple sections.

Components

• ui-auth
• ui-avatar
• ui-brand
• ui-button
• ui-buttons
• ui-card-body
• ui-card-footer
• ui-card-header
• ui-card
• ui-code
• ui-comment-form
• ui-comment
• ui-content
• ui-data
• ui-debug
• ui-dialog-form
• ui-dialog-progress
• ui-dropdown
• ui-footer
• ui-form
• ui-header
• ui-hero
• ui-label
• ui-layout
• ui-link
• ui-links
• ui-list-item
• ui-list
• ui-loading-icon
• ui-loading
• ui-markdown
• ui-page-sidebar-route
• ui-page-sidebar
• ui-render
• ui-sidebar-item
• ui-sidebar
• ui-tabs
• ui-user