Introduce MPT support (XLS-33d): (#5143)

Amendment:
- MPTokensV1

New Transactions:
- MPTokenIssuanceCreate
- MPTokenIssuanceDestroy
- MPTokenIssuanceSet
- MPTokenAuthorize

Modified Transactions:
- Payment
- Clawback

New Objects:
- MPTokenIssuance
- MPToken

API updates:
- ledger_entry
- account_objects
- ledger_data

Other:
- Add += and -= operators to ValueProxy

Read full spec: https://github.com/XRPLF/XRPL-Standards/tree/master/XLS-0033d-multi-purpose-tokens

---------
Co-authored-by: Shawn Xie <shawnxie920@gmail.com>
Co-authored-by: Howard Hinnant <howard.hinnant@gmail.com>
Co-authored-by: Ed Hennis <ed@ripple.com>
Co-authored-by: John Freeman <jfreeman08@gmail.com>

include/xrpl/protocol/LedgerFormats.h

@@ -174,6 +174,18 @@ enum LedgerSpecificFlags {
 
     // ltNFTOKEN_OFFER
     lsfSellNFToken = 0x00000001,
+
+    // ltMPTOKEN_ISSUANCE
+    lsfMPTLocked = 0x00000001, // Also used in ltMPTOKEN
+    lsfMPTCanLock = 0x00000002,
+    lsfMPTRequireAuth = 0x00000004,
+    lsfMPTCanEscrow = 0x00000008,
+    lsfMPTCanTrade = 0x00000010,
+    lsfMPTCanTransfer = 0x00000020,
+    lsfMPTCanClawback = 0x00000040,
+
+    // ltMPTOKEN
+    lsfMPTAuthorized = 0x00000002,
 };
 
 //------------------------------------------------------------------------------