Auro design tokens: Spike how to architect repo with multi theme support

[Brandon Shields]

Is your feature request related to a problem? Please describe.

I want all my themes in the design token repo.
So that I can support the business with any theme we want in the future.

Describe the solution you'd like

A solution where all themes are organized in the repo
A dark and light mode architecture is available for every theme
When a new theme is requested there is a clear pattern to follow.

Describe alternatives you've considered

No response

Additional context

This is to support excursion and jetstream #151 #152

Exit criteria

We have demo'd the POC to the Auro team
We have demo'd the POC tokens that the app team will consume.
We have demo'd the POC tokens that the jetstream team will consume.
We have demo'd the POC tokens that the jetstream apps team will consume.
Any findings are added to #151 and #152
We are ready to pass off this work to offshore team.
Figure out a release strategy. Will we need a major release or do we have a way to add jetstream and excursion without a major release?
We should also have some thoughts, or a bullet point on docs, for how we handle future releases which add new themes, or changes which only impact a single theme