Move AddAndGetDestinationForScript from wallet to outputype module

Makes AddAndGetDestinationForScript use a generic CKeyStore rather than
the wallet, and makes it always add the script to the keystore, rather
than only adding related (redeem) scripts.

src/wallet/rpcwallet.cpp

@@ -1363,8 +1363,7 @@ static UniValue addmultisigaddress(const JSONRPCRequest& request)
 
     // Construct using pay-to-script-hash:
     CScript inner = CreateMultisigRedeemscript(required, pubkeys);
-    pwallet->AddCScript(inner);
-    CTxDestination dest = pwallet->AddAndGetDestinationForScript(inner, output_type);
+    CTxDestination dest = AddAndGetDestinationForScript(*pwallet, inner, output_type);
     pwallet->SetAddressBook(dest, label, "send");
 
     UniValue result(UniValue::VOBJ);