* Introduces amendment `XRPFees`
* Convert fee voting and protocol messages to use XRPAmounts
* Includes Validations, Change transactions, the "Fees" ledger object,
and subscription messages
* Improve handling of 0 drop reference fee with TxQ. For use with networks that do not want to require fees
* Note that fee escalation logic is still in place, which may cause the
open ledger fee to rise if the network is busy. 0 drop transactions
will still queue, and fee escalation can be effectively disabled by
modifying the configuration on all nodes
* Change default network reserves to match Mainnet
* Name the new SFields *Drops (not *XRP)
* Reserve SField IDs for Hooks
* Clarify comments explaining the ttFEE transaction field validation
Fixes#4005
Makes it possible for internal RPC Error Codes to associate
themselves with a non-OK (200) HTTP status code. There are
quite a number of RPC responses in addition to tooBusy that
now have non-OK HTTP status codes.
The new return HTTP return codes are only enabled by including
"ripplerpc": "3.0" or higher in the original request.
Otherwise the historical value, 200, continues to be returned.
This ensures that this is not a breaking change.
featureDisallowIncoming is a new amendment that would allow users to opt-out of incoming Checks, Payment Channels, NFTokenOffers, and trust lines. This commit includes tests.
Adds four new AccountSet Flags:
1. asfDisallowIncomingNFTOffer
2. asfDisallowIncomingCheck
3. asfDisallowIncomingPayChan
4. asfDisallowIncomingTrustline
