MediaWiki:Gadget-wiki activity

Adds a close approximation of the old WikiActivity. The new version is located at the same location as the old one but will take a second or so longer to load. This gadget also changes the link to Special:RecentChanges in the local navigation bar to Special:WikiActivity. Please note that this gadget is still in beta. This gadget is simply an easy way to install WikiActivity from the Fandom Dev wiki with a few additional features.