Extract all styles from index html

[rhyshort]

Overview

Configure webpack to insert generated css styles as links rather than inline. This completely removes the need for CSP policies with style-src unsafe-inline, enabling users to have more restrictive CSP policies.

Testing recommendations

To verify if the styles are correctly loaded a server with the CSP policy preventing unsafe-inline styles needs to be used, javascript needs to be disabled in the browser to verify the styles are correctly applied for the nonscript use case.

GitHub issue number

n/a

Related Pull Requests

Checklist

• [x] Code is written and works correctly;
• [ ] Changes are covered by tests;
• [ ] Documentation reflects the changes;
• [ ] Update rebar.config.script with the correct tag once a new Fauxton release is made