support deeply nested colors in tailwind service

[olets]

Tailwind supports deeply nested colors; our Tailwind service doesn't. Changing getColors to use a recursive function would add support for deeply nested colors.

Example: the AHIP design system has things like "blue" and "dark blue", which we set up as

      blue: {
        DEFAULT: '#5fb1c3',
        // … several levels of blue
        dark: {
          DEFAULT: '#004b66',
          // … several levels of dark blue
        },
      },