Initial integration of Patterfly's dark mode in 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.

Acceptance criteria:

• integrate the PF Release Version with dark mode
• add over arching style updates to fix borders and background color variables
• re-evaluate serenas slide deck: https://docs.google.com/presentation/d/1ZeJUVKPput7g6w9kHl3NmGbjggdJ80WH1pmZPe_hWHQ/edit#slide=id.g5c9f6cd93e_0_286
• re-evaluate spreadsheet of issues: https://docs.google.com/spreadsheets/d/1fBCPPb4Z1sqUDKgQkpueGe8VQZo4pBUA9PV4vnFCnDw/edit#gid=0
• Create styling to support the Events sections with dark mode enabled
• Create styling to support all modals with dark mode enabled