refactor: use styled components in Badge

[LeandroTorresSicilia]

Changes proposed in this PR:

• use styled components in Badge

• I have followed (at least) the PR section of the contributing guide.

@nexxtway/react-rainbow

[reiniergs]

TruncatedText??

[gustavopch]

In case you don't know, you don't need to import those theme variables. Instead, you could do something like:

color: ${props => props.theme.COLOR_GRAY_4}

Of course you'd have to change the Application component to have a ThemeProvider. Then, when lib is fully refactored with styled-components, it'll be a matter of changing Application to take a theme prop in order to let each consumer customize their themes or implement a dark mode.

[LeandroTorresSicilia]

@gustavopch
That's right, but I think first we should move forward refactoring all components to use styled-components and removing all scss files.
For theming we need to discuss its structure and what will be customizable so it is early to use:
props.theme.COLOR_GRAY_4
although I know that we will need to touch all components again

[TahimiLeonBravo]

#950