Add preset for sport=australian_football

[CloCkWeRX]

https://taginfo.openstreetmap.org/tags/sport=australian_football

While more common for Australia than anywhere else (https://en.wikipedia.org/wiki/Australian_rules_football), a very frequent geographic feature is a multi use sports oval (australian_football in winter, cricket in summer)

These are tricky to tag correctly. For example, https://overpass-turbo.eu/s/ExF shows a very large number of ways tagged with only cricket though it is very likely a number of these are dual use.