Implement colorimetry based on the anonymity status.

If the whistleblower is anonymous and tor2web based submission are allowed the button is BLUE

If the whistleblower is NOT anonymous and tor2web based submission are allowed the button is YELLOW

If the whistleblower is NOT anonymous and tor2web based submission are NOT allowed the button is RED and DISABLED

This fixes: https://github.com/globaleaks/GlobaLeaks/issues/338