Introduce the ExpandedSignerList amendment:

The amendment increases the maximum sign of an account's signer
list from 8 to 32.

Like all new features, the associated amendment is configured with
a default vote of "no" and server operators will have to vote for
it explicitly if they believe it is useful.

src/ripple/protocol/impl/InnerObjectFormats.cpp

@@ -28,6 +28,7 @@ InnerObjectFormats::InnerObjectFormats()
         {
             {sfAccount, soeREQUIRED},
             {sfSignerWeight, soeREQUIRED},
+            {sfWalletLocator, soeOPTIONAL},
         });
 
     add(sfSigner.jsonName.c_str(),