Add and refactor tests for features of element "chip-group" on a test-site

[annav00]

Add and refactor tests for features of element "chip-group" on a test-site:

• [ ] center-active (y/n)
• [ ] column (y/n)
• [ ] theme (dark/light)
• [ ] max (0-n)
• [ ] next-icon (icon)
• [ ] prev-icon (icon)
• [ ] show-arrows (y/n)
• [ ] value ()

v-slide-group provides a baseline for component v-chip-group. Probably the ChipGroup element should extend the SlideGroup element.