rpc: Enhance metadata of the dumptxoutset output

The following data is added:
- A newly introduced utxo set magic
- A version number
- The network magic
- The block height

src/kernel/chainparams.cpp

@@ -542,3 +542,33 @@ std::unique_ptr<const CChainParams> CChainParams::TestNet()
 {
     return std::make_unique<const CTestNetParams>();
 }
+
+std::vector<int> CChainParams::GetAvailableSnapshotHeights() const
+{
+    std::vector<int> heights;
+    heights.reserve(m_assumeutxo_data.size());
+
+    for (const auto& data : m_assumeutxo_data) {
+        heights.emplace_back(data.height);
+    }
+    return heights;
+}
+
+std::optional<ChainType> GetNetworkForMagic(MessageStartChars& message)
+{
+    const auto mainnet_msg = CChainParams::Main()->MessageStart();
+    const auto testnet_msg = CChainParams::TestNet()->MessageStart();
+    const auto regtest_msg = CChainParams::RegTest({})->MessageStart();
+    const auto signet_msg = CChainParams::SigNet({})->MessageStart();
+
+    if (std::equal(message.begin(), message.end(), mainnet_msg.data())) {
+        return ChainType::MAIN;
+    } else if (std::equal(message.begin(), message.end(), testnet_msg.data())) {
+        return ChainType::TESTNET;
+    } else if (std::equal(message.begin(), message.end(), regtest_msg.data())) {
+        return ChainType::REGTEST;
+    } else if (std::equal(message.begin(), message.end(), signet_msg.data())) {
+        return ChainType::SIGNET;
+    }
+    return std::nullopt;
+}