wallet: Add IsAddressUsed / SetAddressUsed methods

This simplifies code and adds a less cumbersome interface for accessing
address used information than CWallet AddDestData / EraseDestData /
GetDestData methods.

There is no change in behavior. Lower-level walletdb DestData methods
are also still available and not affected by this change. If there is
interest in consolidating destdata logic more and making it internal to
walletdb, #18608 could be considered as a followup.

src/wallet/test/wallet_tests.cpp

@@ -390,7 +390,7 @@ BOOST_AUTO_TEST_CASE(LoadReceiveRequests)
     CTxDestination dest = PKHash();
     LOCK(m_wallet.cs_wallet);
     WalletBatch batch{m_wallet.GetDatabase()};
-    m_wallet.AddDestData(batch, dest, "misc", "val_misc");
+    m_wallet.SetAddressUsed(batch, dest, true);
     m_wallet.SetAddressReceiveRequest(batch, dest, "0", "val_rr0");
     m_wallet.SetAddressReceiveRequest(batch, dest, "1", "val_rr1");