Add theming for chips

[bethcollins92]

Done

• Added theming for chips with different shades of border/background/text for each chip type
• Added theme default setting for chips
• Added example in the docs
• Added an example for the dismiss chip as this was missing

Fixes #4158

QA

• Open demo
• Check the dark chip example
• Check adding is-dark or is-light class names work as expected
• Review updated documentation:
  • Chip documentation - new example for the dismiss chip and dark theme

Check if PR is ready for release

If this PR contains Vanilla SCSS code changes, it should contain the following changes to make sure it's ready for the release:

• PR should have one of the following labels to automatically categorise it in release notes:
  • Feature 🎁, Breaking Change 💣, Bug 🐛, Documentation 📝, Maintenance 🔨.
• Vanilla version in package.json should be updated relative to the most recent release, following semver convention:
  • if CSS class names are not changed it can be bugfix relesase (x.x.X)
  • if CSS class names are changed/added/removed it should be minor version (x.X.0)
  • see the wiki for more details
• Any changes to component class names (new patterns, variants, removed or added features) should be listed on the what's new page.
• Documentation side navigation should be updated with the relevant labels.

[webteam-app]

Demo starting at https://vanilla-framework-4168.demos.haus

[bartaz]

@bethcollins92 I think we should have dark chips in the variants example as well:
https://vanilla-framework-4168.demos.haus/docs/examples/patterns/chip/variants

I guess just duplicate whole thing inside the dark strip (in the same example file below current stuff).

[bartaz]

This part seems extremely repetitive, but I'm not sure if we can do anything about it - we do need separate color treatment for each of those variants…

[bethcollins92]

I had the same feeling when writing it but couldn't figure out a way around it!

[bartaz]

LGTM, thanks!

[lyubomir-popov]

Why does the close button at the bottom have class .is-light?

[lyubomir-popov]

I think there's an extra class that makes the close grey on red... not very readable. Suggestion to remove it in the code.

[bethcollins92]

@lyubomir-popov The .is-light class was in the wrong place. Fixed it now