Support aliases for colors #11

Now, colors palettes are enumerated from 0 to palette.length - 1.

We want to support aliases for color arrays indices.

Example:

const colors = ['#aaa', '#bbb', '#bbb']
colors.aliases = ['default', 'active', 'disabled']

<PaletteSwatch token={"gray"} value={colors} aliasesKey='aliases' />

or

<ColorSwatch token={"error"} value={"#C0100F"} alias={"red"} />

Proposal

• extend ColorSwatch with alias property and display alias under the default name

• extend PaletteSwatch with aliasesKey prop which will be used to read aliases from colors array and pass it to ColorSwatch