Better Gatry wót GataQuadrada

Gatry website lacks some functionalities, and could use the following quality of life improvements (provided by this extension):
- Dark Mode and Dark Mode toggle;
- Users block, to silence the rampant amount of toxic fakes in the community;
- Verified users seal, so we know the difference between actual user and a fake with similar name and avatar;
- Link preview, so we know before opening random URLs (given the mods aren't present all the time);
- Avatar preview on account page, so the user knows if the image has good framing;
- Posts download;
- Share button;
- Notification counter on Plugin icon;
- Minor QoL improvements.

This extension also fixes a huge bug with the AJAX Requests, that, sometimes, will duplicate content on the user's screen.