Feature Enhancment: Unify styles and theme into a dynamic and configurable config

[orpheus]

Feature Enhancement

Move hardcoded style constants to a configurable MUI theme.

Create a file (either json or javascript) that allows an individual to set certain elements of the theme from outside the MUI Config (the MUI Config reads from this file). Reference Davi for which elements should be 'settable' (primary/secondary color, etc)

Current Behavior

With the current styling solution, DDX is using a mix of MUI theme variables (in the form of const style => theme> ({...}) and custom style variables (i.e those found in src/assets/jss/ddx-react.jsx).

Reasoning

To create a single source of truth (as much as possible) for the styling and theming of an app that can be dynamically configured by an outside source to spawn off variations of the app with personally-customizable elements.