A WebExtension reimplementation of the Expire history by days Addon. Removes URLs from history that are older than a certain age.
Addon requires user to set maximum age of history before it will do anything
This Addon uses the WebExtensions history API, which has only been added in FF 49. Users of older versions of FF can use 'Expire history by days' as linked above.
In an attempt to minimize any performance impact, this Addon waits 30 minutes after FF startup before scanning history the first time, and will subsequently scan every 30 minutes after that.
