POC: theme switcher

[jordanjones243]

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

Switching a theme should be as easy as swapping out one design token lib for another.

Describe the solution you'd like

Use an auro-select element that allows the user to toggle which theme they would like to use and have Javascript that will load the correct design token script, depending on the user's selection.

Describe alternatives you've considered

Refer to this original ticket for an alternate component and implementation idea:

• Design token value map AuroDesignTokens#104

Exit criteria

For this issue to be closed, a user must be able to subscribe to an alternate set of design tokens and HTML custom elements within the scope of that project will change themes based on those tokens.