Merge #19290: wallet: move BDB specific classes to bdb.{cpp/h}

61c16339da walletdb: Move BDB specific things into bdb.{cpp/h} (Andrew Chow)
8f033642a8 walletdb: moveonly: Move BerkeleyBatch Cursor and Txn funcs to cpp (Andrew Chow)
25a655794a walletdb: move IsWalletLoaded to walletdb.cpp (Andrew Chow)
f6fc5f3849 walletdb: Add IsBDBWalletLoaded to look for BDB wallets specifically (Andrew Chow)
c3538f435a walletdb: Make SpliWalletFilePath non-static (Andrew Chow)

Pull request description:

  Moves the BDB specific classes from db.{cpp/h} to bdb.{cpp/h}.

  To do this, `SplitWalletFilePath` is first made non-static. Then `IsWalletLoaded` functionality is moved to `IsBDBWalletLoaded` which is called by `IsWalletLoaded`. Then the bulk of db.{cpp/h} is moved to a new file bdb.{cpp/h}.

  While doing some moveonly stuff, an additional commit moves the `*Cursor` and `Txn*` implementations out of the header file and into the cpp file.

  Part of #18971

ACKs for top commit:
  laanwj:
    Code review ACK 61c16339da
  promag:
    Code review ACK 61c16339da.
  meshcollider:
    utACK 61c16339da

Tree-SHA512: cb676cd34c9cd3c838a4fef230d84711efe4cf0d2eefa64ebfd7f787ddc6f7379db0b29454874ddc46ca7ffee0f18f6f3fb96a85513cd10164048948fd03a80c

src/qt/rpcconsole.cpp

@@ -24,6 +24,7 @@
 #include <univalue.h>
 
 #ifdef ENABLE_WALLET
+#include <wallet/bdb.h>
 #include <wallet/db.h>
 #include <wallet/wallet.h>
 #endif