Merge bitcoin#17034: [BIP 174] PSBT version, proprietary, and xpub fields

8152117 Merge global xpubs in joinpsbts and combinepsbts (Andrew Chow)
d8043dd Add global xpub test vectors from BIP (Andrew Chow)
35670df Add global_xpubs to decodepsbt (Andrew Chow)
9038485 Implement serializations for PSBT_GLOBAL_XPUB (Andrew Chow)
c5c63b8 Implement operator< for KeyOriginInfo and CExtPubKey (Andrew Chow)
d3dbb16 Separate individual HD Keypath serialization into separate functions (Andrew Chow)
a69332f Store version bytes and be able to serialize them in CExtPubKey (Andrew Chow)
5fdaf6a moveonly: Move (Un)Serialize(To/From)Vector, (De)SerializeHDKeypaths to psbt module (Andrew Chow)
94065cc Test for proprietary field (Andrew Chow)
a4cf810 Output proprietary type info in decodepsbt (Andrew Chow)
aebe758 Implement PSBT proprietary type (Andrew Chow)
10ba0b5 Output psbt version in decodepsbt (Andrew Chow)
df84fa9 Add GetVersion helper to PSBT (Andrew Chow)
c3eb416 Implement PSBT versions (Andrew Chow)
3235847 Types are compact size uints (Andrew Chow)

Pull request description:

  Implements the changes to BIP 174 proposed in bitcoin/bips#849 and bitcoin/bips#784

  Implements `PSBT_GLOBAL_VERSION`, `PSBT_GLOBAL_PROPRIETARY`, `PSBT_IN_PROPRIETARY`, `PSBT_OUT_PROPRIETARY`, and `PSBT_GLOBAL_XPUB`. The `PSBT_GLOBAL_XPUB` changes are merged in from bitcoin#16463.

  Also includes the test vectors added to BIP 174 for these fields.

  A number of additional changes to keypath and xpub serialization are made to support `PSBT_GLOBAL_XPUB`.

ACKs for top commit:
  laanwj:
    Code review ACK 8152117

Tree-SHA512: bd71c3f26030fc23824e76a30d3d346a753e1db224ecee163d6813348feb52d3f4cf4e739a4699e2cff381197ce2a7ea4a92a054f2c3e1db579e91e92a0945e0

Author: laanwj

src/psbt.cpp

@@ -32,6 +32,13 @@ bool PartiallySignedTransaction::Merge(const PartiallySignedTransaction& psbt)
     for (unsigned int i = 0; i < outputs.size(); ++i) {
         outputs[i].Merge(psbt.outputs[i]);
     }
+    for (auto& xpub_pair : psbt.m_xpubs) {
+        if (m_xpubs.count(xpub_pair.first) == 0) {
+            m_xpubs[xpub_pair.first] = xpub_pair.second;
+        } else {
+            m_xpubs[xpub_pair.first].insert(xpub_pair.second.begin(), xpub_pair.second.end());
+        }
+    }
     unknown.insert(psbt.unknown.begin(), psbt.unknown.end());
 
     return true;
@@ -401,3 +408,11 @@ bool DecodeRawPSBT(PartiallySignedTransaction& psbt, const std::string& tx_data,
     }
     return true;
 }
+
+uint32_t PartiallySignedTransaction::GetVersion() const
+{
+    if (m_version != std::nullopt) {
+        return *m_version;
+    }
+    return 0;
+}