[SPIKE] Scope changes needed for dark mode in the admin console

As a developer, I want to be able to scope the changes needed to enable dark mode for the admin console. As such, I need to investigate how much of the console will display dark mode using PF variables and also define a list of gotcha pages/components which will need special casing above and beyond PF variable settings.

Mike Coker has worked on a POC from the PF point of view on both the admin and dev console, and the screenshot results are listed below along with the repo branch. Also listed is a document covering some of the common issues found when putting together the admin console POC. 

Background POC work completed for reference:

PatternFly Dark Theme Handbook: https://docs.google.com/document/d/1mRYEfUoOjTsSt7hiqjbeplqhfo3_rVDO0QqMj2p67pw/edit

Admin Console -> Workloads & Pods

• Screenshots: https://docs.google.com/presentation/d/1BoOpXpX96_uNUhVJiEqGUCZ-JMYh1A78fXJhk3H86K8/edit#slide=id.p
• Github branch: https://github.com/mcoker/console/tree/dark-theme
• Github PR for Dark Theme WIP by Vikram: https://github.com/openshift/console/pull/10947

Dev Console -> Gotcha pages: Observe Dashboard and Metrics, Add, Pipelines: builder, list, log, and run

• Screenshots: https://docs.google.com/presentation/d/13jagAf_JEu82hd_KpEHRmj25xCEqwImWpNufzVopuUs/edit#slide=id.p
• Github branch: https://github.com/openshift/console/pull/10815
• Evaluation: https://docs.google.com/spreadsheets/d/1fBCPPb4Z1sqUDKgQkpueGe8VQZo4pBUA9PV4vnFCnDw/edit#gid=0

Acceptance criteria:

1.  Investigate a UI to toggle dark mode/light mode
2.  Piggy back on Mikes story and verify the PF pages work with dark mode as noted above
3.  Create list of custom components that need additional work to allow for dark mode
4.  Provide a readout for the amount of work to support dark mode that can be sized by the team in grooming
5.  Create an epic above the spike together with stories and sub-stories