More customization

-As per u/usmlebro's idea, there is now an ability to change the HTML attributes of heatmap in the Anki Addon config. No more comically large heatmaps 🥇

-Extended heatmap now works better with other addons such as Countdown To Events and Exams.

-Extended Heatmap now uses a more modern GUI_hook

-Config has a comprehensive guide with an image telling users how to refresh browser. If you have any problems with the deck browser rendering (with all those addons, I found it can occasionally freeze), I added a quick explanation in the config of the addon on how to escape that. (just press sync or the "decks" button