Share OfflineWalletOperations

src/bdk.udl

@@ -98,6 +98,7 @@ callback interface BdkProgress {
 interface OnlineWallet {
     [Throws=BdkError]
     constructor(string descriptor, Network network, DatabaseConfig database_config, BlockchainConfig blockchain_config);
+    string get_new_address();
     Network get_network();
     [Throws=BdkError]
     void sync(BdkProgress progress_update, u32? max_address_param);