wallet: AvailableCoins, add arg to include/skip locked coins

src/wallet/spend.h

@@ -68,6 +68,8 @@ struct CoinFilterParams {
     bool only_spendable{true};
     // By default, do not include immature coinbase outputs
     bool include_immature_coinbase{false};
+    // By default, skip locked UTXOs
+    bool skip_locked{true};
 };
 
 /**