Add optional parameter to pass gas amount

[jessgusclark]

Adds a parameter to pass the amount of gas used to send the payment token from the UX to the SDK.

Usage, from the UX, the Confirm Modal:

const confirmObject: OverriddableTransactionOptions = {
      gasPrice: BigNumber.from(gasPrice),
      gasLimit: BigNumber.from(gasLimit),
      tokenPayment: {
        tokenContract: feeContract,
        tokenAmount: txCostInRif,
        tokenGasIncrease: 1.1, // 10%
     },
}

The key here is going to be to see what percentage we need to increase it for USDRIF. I suspect this is happening because USDRIF is a proxy contract and so we are not calling transfer directly on the contract, but being passed through to a child contract.

[rodrigoncalves]

LG

[jessgusclark]

@rodrigoncalves Thanks, deployed here: @rsksmart/[email protected]