[FIX] APISite: Don't use deprecated generators
[FIX] APISite: Don't use deprecated generators

With d298facc the Image/CategoryPageGenerator have been deprecated, but
the APISite still used these generators.

Change-Id: I6746f619dc632fa7cedcc015b42cf745cb19ccf3

VcamX/pywikibot-core,hasteur/g13bot_tools_new,wikimedia/pywikibot-core,xZise/pywikibot-core,valhallasw/pywikibot-core,jayvdb/pywikibot-core,hasteur/g13bot_tools_new,Darkdadaah/pywikibot-core,TridevGuha/pywikibot-core,Darkdadaah/pywikibot-core,magul/pywikibot-core,wikimedia/pywikibot-core,happy5214/pywikibot-core,npdoty/pywikibot,npdoty/pywikibot,smalyshev/pywikibot-core,h4ck3rm1k3/pywikibot-core,icyflame/batman,hasteur/g13bot_tools_new,h4ck3rm1k3/pywikibot-core,trishnaguha/pywikibot-core,jayvdb/pywikibot-core,magul/pywikibot-core,happy5214/pywikibot-core,emijrp/pywikibot-core,PersianWikipedia/pywikibot-core,darthbhyrava/pywikibot-local