Add option to override path to colors in config.

[dsturm]

To be able to declare colors independently of the Tailwind´s overall colors and specific for the WordPress Block Editor, this PR adds an option to specify the path in the tailwind config object, with the theme key as root.

For example you can declare the palettes´ colors in:

module.exports = {
  theme: {
    palette: {
      colors: {
        indigo: '#667eea',
      }
    }
  }
}

and set the option to:

{
  /* ... */
  tailwind: {
    config: './tailwind.config.js',
    shades: false,
    path: 'palette.colors'
  }
  /* ... */
}

[Log1x]

Awesome! Thanks man