fix(styles,theme): add S2 tokens and theme

[TarunAdobe]

Introduce spectrum-two styles as a SWC theme.

Description

This PR introduces a new system for sp-theme in the form of spectrum-two. For this new system the PR is consuming the tokens from spectrum-css/tokens which enables us to include the pre-foundation changes to SWC consumers.

NOTE: These changes do NOT affect delivery of spectrum or express system in SWC themes.

Todos:

• Add a script to generate tokens-v2 from the @spectrum-css's next versions.
• Add spectrum-two theme that takes v2 tokens.
• Update storybook decorator and documentation site to include spectrum-two theme.
• Update visual ci test to include spectrum-two theme.

Motivation and context

How has this been tested?

• Test case 1
  1. Go here
  2. Toggle the theme
• Test case 2
  1. Go here
  2. Toggle the theme

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Chore (minor updates related to the tooling or maintenance of the repository, does not impact compiled assets)

Checklist

• I have signed the Adobe Open Source CLA.
• My code follows the code style of this project.
• If my change required a change to the documentation, I have updated the documentation in this pull request.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.
• I have reviewed at the Accessibility Practices for this feature, see: Aria Practices

Best practices

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[Rajdeepc]

Good start! Let's also think about creating some documentation around this in parallel!

[Rajdeepc]

Thanks for adding these tests and also the dev mode warning for spectrum-two.

[Westbrook]

There is now a "stable" 14.0 release, should CSS get you a new "future" release with that info?

[Rajdeepc]

This is a import for spectrum-two. I think the stable 14.0 version is importing S1 tokens