Allow fractional fees to be charged to _either_ sender or receiver

[ljianghedera]

Problem

Please refer to the description in services issue #1926: hashgraph/hedera-services#1926

Solution

message FractionalFee {
  Fraction fractional_amount = 1; // The fraction of the transferred units to assess as a fee
  int64 minimum_amount = 2; // The minimum amount to assess
  int64 maximum_amount = 3; // The maximum amount to assess (zero implies no maximum)
  bool netOfTransfers = 4; // If true, assesses the fee to the sender, so the receiver gets the full amount from the token transfer list, and the sender is charged an additional fee; if false, the receiver does NOT get the full amount, but only what is left over after paying the fractional fee
}

Alternatives

No response