Remove unnecessary generality from ItemizableFeeCharging

[tinker-michaelj]

Summary
The ItemizableFeeCharging allows charging any combination of network, node, and service fees to either the designated payer or submitting node for a transaction.

However, only four combinations are actually used:

1. Node didn't perform due diligence --> Submitting node charged (up to) network fee.
2. Payer submitted duplicate txn or was unwilling/unable to pay service fee --> Payer charged network fee and (up to) node fee.
3. Txn not scheduled and payer can afford all fees --> Payer charged all fees.
4. Txn was scheduled and payer can afford service fee --> Payer charged service fee.

It will be simpler, safer, and more performant to implement methods for just these cases.

Possible resolution
Refactor ItemizableFeeCharging to support only these charging actions.