Various enhancements

Features

• Support rich content in tooltip.
• Add resetScrollPosition function in SplitContent.
• Move tooltip back to body in afterUpdate.
• Add IconSort and IconPlus.
• Review icons to standardises most of them and ensure they match the overall design and maintain a consistent line thickness.
• Option to display a maximum number of visible toasts.

Style

• Change tooltip colors to dropdown colors.
• Add tooltip CSS variables.
• Improve clicked icon buttons visibility in light theme.
• Narrow toasts width on medium screen.

Build

• Bump dompurify.
• Bump dev dependencies.

Test

• Migrate to testing-library v5.

Chore

• Change content of CODEOWNERS to be compliant (Gix + Nns).
• Do not use token on fork PRs.
• Lint 'element' is assigned a value but never used in a test.
• Do not accept lint warnings in CI
• Remove local screenshots from repo.
• Set description in package.json.