Disallow bech32m addresses for legacy wallet things

We don't want the legacy wallet to ever have bech32m addresses so don't
allow importing them. This includes addmultisigaddress as that is a
legacy wallet only RPC

Additionally, bech32m multisigs are not available yet, so disallow them
in createmultisig.

src/outputtype.cpp

@@ -108,3 +108,19 @@ CTxDestination AddAndGetDestinationForScript(FillableSigningProvider& keystore,
     } // no default case, so the compiler can warn about missing cases
     assert(false);
 }
+
+std::optional<OutputType> OutputTypeFromDestination(const CTxDestination& dest) {
+    if (std::holds_alternative<PKHash>(dest) ||
+        std::holds_alternative<ScriptHash>(dest)) {
+        return OutputType::LEGACY;
+    }
+    if (std::holds_alternative<WitnessV0KeyHash>(dest) ||
+        std::holds_alternative<WitnessV0ScriptHash>(dest)) {
+        return OutputType::BECH32;
+    }
+    if (std::holds_alternative<WitnessV1Taproot>(dest) ||
+        std::holds_alternative<WitnessUnknown>(dest)) {
+        return OutputType::BECH32M;
+    }
+    return std::nullopt;
+}