Introduce AMM support (XLS-30d): (#4294)

Add AMM functionality:
- InstanceCreate
- Deposit
- Withdraw
- Governance
- Auctioning
- payment engine integration

To support this functionality, add:
- New RPC method, `amm_info`, to fetch pool and LPT balances
- AMM Root Account
- trust line for each IOU AMM token
- trust line to track Liquidity Provider Tokens (LPT)
- `ltAMM` object

The `ltAMM` object tracks:
- fee votes
- auction slot bids
- AMM tokens pair
- total outstanding tokens balance
- `AMMID` to AMM `RootAccountID` mapping

Add new classes to facilitate AMM integration into the payment engine.
`BookStep` uses these classes to infer if AMM liquidity can be consumed.

The AMM formula implementation uses the new Number class added in #4192.
IOUAmount and STAmount use Number arithmetic.

Add AMM unit tests for all features.

AMM requires the following amendments:
- featureAMM
- fixUniversalNumber
- featureFlowCross

Notes:
- Current trading fee threshold is 1%
- AMM currency is generated by: 0x03 + 152 bits of sha256{cur1, cur2}
- Current max AMM Offers is 30

---------

Co-authored-by: Howard Hinnant <howard.hinnant@gmail.com>

src/test/app/TheoreticalQuality_test.cpp

@@ -28,6 +28,7 @@
 #include <ripple/ledger/Sandbox.h>
 #include <ripple/protocol/Feature.h>
 #include <ripple/protocol/jss.h>
+#include "ripple/app/paths/AMMContext.h"
 #include <test/jtx.h>
 #include <test/jtx/PathSet.h>
 
@@ -245,6 +246,7 @@ class TheoreticalQuality_test : public beast::unit_test::suite
         std::optional<Quality> const& expectedQ = {})
     {
         PaymentSandbox sb(closed.get(), tapNONE);
+        AMMContext ammContext(rcp.srcAccount, false);
 
         auto const sendMaxIssue = [&rcp]() -> std::optional<Issue> {
             if (rcp.sendMax)
@@ -265,6 +267,7 @@ class TheoreticalQuality_test : public beast::unit_test::suite
             /*defaultPaths*/ rcp.paths.empty(),
             sb.rules().enabled(featureOwnerPaysFee),
             /*offerCrossing*/ false,
+            ammContext,
             dummyJ);
 
         BEAST_EXPECT(sr.first == tesSUCCESS);