Create decimal.MulInt #2407
Description
Summary
Within staking we often convert an sdk.Int to a sdk.Decimal, to just multiply it with another already known decimal. This is inefficient (as theres extra memory allocation, and the multiplication equation for 2 dec's is more complex than a dec * int), and instead we should just support the simpler / faster Decimal * Int operation as well. I propose the name "MulInt" for this operation.