feat: Updates Avatar to support responsive patterns

[scottlovegrove]

Closes #605

Short description

Updates the Avatar component to use the newer way of doing reactist components, using css variables etc. It also adds the abaility to use the responsive elements that have been introduced with v11 so that an avatar's size can dynamically change based on the screen size.

One thing to note, I have intentionally left the size values as is otherwise this would have resulted in a breaking change.

PR Checklist

• Added tests for bugs / new features
• Updated docs (storybooks, readme)
• Executed npm run validate and made sure no errors / warnings were shown
• Described changes in CHANGELOG.md
• Bumped version in package.json and package-lock.json (npm --no-git-tag-version version <major|minor|patch>) ref
• Updated all static build artifacts (npm run build-all)

Versioning

Left versioning alone, it can be released when one is next done.

[gnapse]

@scottlovegrove you marked my latest comments as resolved, but I do not see any new changes having been pushed after them. Perhaps you forgot to push something?

[scottlovegrove]

@scottlovegrove you marked my latest comments as resolved, but I do not see any new changes having been pushed after them. Perhaps you forgot to push something?

@gnapse I was waiting for an answer about the snapshot tests and whether I should just remove them.

[gnapse]

I do not see value on them in this case, especially in the cases where I commented (the ones where you are already making an extra assertion that validates what's described in the test case title).

[scottlovegrove]

I do not see value on them in this case, especially in the cases where I commented (the ones where you are already making an extra assertion that validates what's described in the test case title).

I have removed them then and pushed the changes for which I'd marked your comments as resolved.