[Feature]: Allow feegrant for whitelisted contracts

[VegeBun-csj]

Summary

Refer this:
CosmWasm/wasmd#1571

Problem Definition

Is there a plan to promote this in the current feegrant?
Existing implementations do not prevent grantees from abusing fees in contract transactions.

Proposed Feature

CosmWasm/wasmd#1571

[tac0turtle]

thanks for opening this issue. the feature is quite interesting. Is there a reason why this can not be implemented in cw already? Having cw specific features in the base sdk creates an implicit dependency graph that confuses users not using cosmwasm