Fix the ability to release new theme packages

[jpzwarte]

• Stop automatically importing tokens during the build
• Store the imported tokens in packages/tokens/src folder
• Build the themes from packages/tokens/src

Fixes #2588

[changeset-bot]

🦋 Changeset detected

Latest commit: bdb09e8

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 13 packages

Name	Type
@sl-design-system/bingel-dc	Minor
@sl-design-system/bingel-int	Minor
@sl-design-system/clickedu	Minor
@sl-design-system/editorial-suite	Minor
@sl-design-system/itslearning	Minor
@sl-design-system/kampus	Minor
@sl-design-system/magister	Minor
@sl-design-system/max	Minor
@sl-design-system/my-digital-book	Minor
@sl-design-system/neon	Minor
@sl-design-system/sanoma-learning	Minor
@sl-design-system/teas	Minor
@sl-design-system/tig	Minor

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