[OPR-203]: Refactors inits of RetryOperation
[OPR-203]: Refactors inits of RetryOperation

No more convenience initializers.

ProcedureKit/ProcedureKit,ProcedureKit/ProcedureKit,ProcedureKit/ProcedureKit,blg-andreasbraun/ProcedureKit,blg-andreasbraun/Operations,danthorpe/Operations,cezarywojcik/Operations,blg-andreasbraun/ProcedureKit,danthorpe/Operations,blg-andreasbraun/Operations,cezarywojcik/Operations,blg-andreasbraun/ProcedureKit,blg-andreasbraun/Operations,cezarywojcik/Operations,danthorpe/Operations