KOSync improvements (#6733)
KOSync improvements (#6733)

* KOSync - allow automatic WiFi enabling, when user requested progress update

* Add "Sync every # pages" setting to menu

* Get rid of unused default variable

* Simplify logic
Frenzie/koreader,NiLuJe/koreader,Frenzie/koreader,koreader/koreader,pazos/koreader,poire-z/koreader,Markismus/koreader,koreader/koreader,NiLuJe/koreader,Hzj-jie/koreader,poire-z/koreader,mwoz123/koreader