Color token updates

[mattrosno]

Summary

Carbon's color tokens are named like $ui-01, $ui-02, $ui-03 and that has led to redundant usage lookup and the names don't help imply how they should be used.

There's also an opportunity to update token naming to better account for a new background layering model.

Job stories

1. When applying a color to a design or style, I want to use usage-specific naming so I can understand what the token is used for without having to frequently reference the usage guide.

Success measures

1. Previous color tokens have deprecation notices but still work in v11
2. Website, code, and Sketch docs are updated to use the new tokens
3. Migration tooling is available for teams to automatically update source code

Sponsoring team

Carbon team

[mattrosno]

Proposals:

• https://www.notion.so/carbondesignsystem/v3-List-of-to-be-tokens-d0897d8b53cc489594ace6340f11b5f6
• https://www.notion.so/carbondesignsystem/Proposals-2-List-of-to-be-tokens-e997ba016e3a48ddb1fb96346eb1e929

Discussions:

• New color token layering models carbon#7743

Issues:

• Update Color Tokens carbon#8148