Move autopay-supporting domains from hardcoded to user-determinable

•Currently the autopay function works on alexandria.io/browser/ and facebook.com, this needs to change from being hard-coded into being determined in preferences
•One listbox should be for "Supported Domains"
•Second listbox should be for "Supported Social Media Networks" (probably should be checkboxes instead of a text list, with just Facebook and Twitter available for now)