wallet: Correct output type for Segwit address

Current OutputTypeFromDestination at outputtype, returns OUTPUT_TYPE_STRING_LEGACY
for Segwit addresses, as p2sh-segwit requires extra info from the wallet to figure
that out, this change adds a correct way to obtain the desired result from the
wallet interface. So far this will be needed from the UI to identify such type,
as currently a user could select this output type to create an address (receivecoinsdialog)
but no display of it exists.

Author: pablomartin4btc

src/interfaces/wallet.h

@@ -101,6 +101,9 @@ class Wallet
     //! Get public key.
     virtual bool getPubKey(const CScript& script, const CKeyID& address, CPubKey& pub_key) = 0;
 
+    //! Get Output type from a Destination.
+    virtual OutputType getOutputType(const CTxDestination& dest) = 0;
+
     //! Sign message
     virtual SigningResult signMessage(const std::string& message, const PKHash& pkhash, std::string& str_sig) = 0;
 

src/wallet/interfaces.cpp

@@ -166,6 +166,13 @@ class WalletImpl : public Wallet
         }
         return false;
     }
+    OutputType getOutputType(const CTxDestination& dest) override
+    {
+        CScript script = GetScriptForDestination(dest);
+        std::unique_ptr<SigningProvider> provider = m_wallet->GetSolvingProvider(script);
+        std::unique_ptr<Descriptor> desc = provider ? InferDescriptor(script, *provider) : InferDescriptor(script, FlatSigningProvider());
+        return desc->GetOutputType().value_or(OutputType::UNKNOWN);
+    }
     SigningResult signMessage(const std::string& message, const PKHash& pkhash, std::string& str_sig) override
     {
         return m_wallet->SignMessage(message, pkhash, str_sig);