[EPIC] Allow users to be able to edit palette and default color theme in existing design system

[aaronreed708]

Suggestion/Concern

Currently it isn't possible in Theme Builder to change a color in a color palette. Only new colors can be added. One of the reasons for the current limitation is the challenge of handling the fallout that could happen due to such a change. It is also likely that the fallout may not be completely managed without human intervention.

For example, if a user changes a color, what happens to all of the molecules that were already using the original color? What if the original color was the primary, secondary or tertiary color defined in the default color theme? Which other default color theme values would be impacted? Which atoms depend on the affected color theme? Which "on" colors would need to be recalculated?

The goal of this issue is to design how a color change could be made by the user, how the application would communicate to the user the impending issues that might arise from the change, what default values could be used until the user makes the manual updates, how is the user made aware of what manual updates need to be made, etc and then implement those designs.

Proposed Solution

When this work is complete, an end user should be able to load an existing design system, add or delete a color from their color palette and modify the primary, secondary and tertiary values in the design system's default color palette. As such changes happen, the user should receive information relevant to the changes that they have made so that they are well aware of what issues that such a change can have on the design system, what default values Theme Builder will use in an effort to keep the design system accessible and what, if any, manual changes/decisions the user may need to make in order to ensure that the updated design system remains accessible

[aaronreed708]

Dependencies
The thought, guidance and designs arising from the following issues will be the basis for this epic.

• [REQUEST] Design UX for changing a color #529
• [TB] Do Design Thinking around color updating #738
• [REQUEST] Correctly handle upstream changes that cause conflicts #664

TODO: we need to create the tasks (and corresponding issues) that will comprise this epic and define the implementation that we are looking to achieve.

[lwnoble]

Figma File: https://www.figma.com/file/Co8gYdDmE64Wv90eWy9FwE/Mentorship---Edit-Theme-Builder-Colors-and-Themes?type=design&node-id=0%3A1&mode=design&t=mVcIZra821J3XrUe-1

[PaulaPaul]

Questions / comments from 'dry run':

• Set the overall context for what we expect from the mentee (writing code in the SDK? creating Figma designs?)
• Include 'what is Hue/Chroma/Luminance'
• What would prevent a mentee/developer/user from creating colors
• Can we create / refine issues for the mentee to get started on?
  • Rendering the AA and AAA
  • Adding the chroma piece
• Can we schedule a session with Paula/Cody/Keith on navigating the SDK
• Work with Keith - is there a video we can use as an overview of the SDK (@aaronreed708?)
• In the Figma, can we note what exists, can or can not edit, and what is new/needed?
  • In the flow for Adding Theme Colors, is there a simplified flow or overview before the complex frames? Toggle for showing light mode/dark mode?
  • What do each of the individual Add buttons do for each section on Light/Dark mode (there are Figma diagrams for these)