• remove unused medal.svg icon.

user.js:
- add reset customization option to achievement slots.
- check if the banner listener is already added, fixes repeatedly triggering the banner prompt.
- fix global rank link triggering banner prompt.

user.js:
- added more customization options for the banner gradient.

changes to user.js:
- add option menu to select actions
- reduce banner gradient opacity
- stop propagating the event at the achievement anchor