sweep: make sweeper aware of unconfirmed parent transactions.

Extend the fee estimator to take into account parent transactions with
their weights and fees.

Do not try to cpfp parent transactions that have a higher fee rate than
the sweep tx fee rate.

sweep/walletsweep.go

@@ -255,7 +255,9 @@ func CraftSweepAllTx(feeRate chainfee.SatPerKWeight, blockHeight uint32,
 		// Now that we've constructed the items required, we'll make an
 		// input which can be passed to the sweeper for ultimate
 		// sweeping.
-		input := input.MakeBaseInput(&output.OutPoint, witnessType, signDesc, 0)
+		input := input.MakeBaseInput(
+			&output.OutPoint, witnessType, signDesc, 0, nil,
+		)
 		inputsToSweep = append(inputsToSweep, &input)
 	}