Clean up theme colors & component hex values

[wbobeirne]

Untracked cleanup

What This Does

• Adds red, yellow, and green colors to palette
  • I've aliased these as success, warning and error to match the figma but it's pretty common for themes to both have named colors and aliased colors so that, for instance, you could have a theme that uses a different palette color for a state, e.g. a purple warning or a blue success. I think we should do this with all of the colors like blue and gray at some point with aliases like primary and brand. We already somewhat do this with text and border.
• Updates all components to use theme.colors.* instead of hard-coded hex values
  • Tweaked Pill component to better match designs overall
    • Renamed color prop to type so that it matches success | warning | error nomenclature
• Removes unused components
  • guardian-ui's <SideBar />
  • gateway-ui's <Input />
  • I removed them as a part of this PR because I wanted to get rid of all hex values, but had no way to visually confirm changes to these since there is currently no way to get these to render. In general I think we should not leave dead code in the project as we can always restore them via git later.

Screenshots

[EthnTuttle]

pulled and tested.

hex colors are dead, long live the theme!