Merge bitcoin/bitcoin#22100: refactor: Clean up new wallet spend, receive files added #21207

b11a195ef4 refactor: Detach wallet transaction methods (followup for move-only) (Russell Yanofsky)

Pull request description:

  This makes `CWallet` and `CWalletTx` methods in `spend.cpp` and `receive.cpp` files into standalone functions.

  It's a followup to [#21207 MOVEONLY: CWallet transaction code out of wallet.cpp/.h](https://github.com/bitcoin/bitcoin/pull/21207), which moved code from `wallet.cpp` to new `spend.cpp` and `receive.cpp` files.

  There are no changes in behavior. This is just making methods into functions and removing circular dependencies created by #21207. There are no comment or documentation changes, either. Removed comments from `transaction.h` are just migrated to `spend.h`, `receive.h`, and `wallet.h`.

  ---

  This commit was split off from #21206 so there are a few earlier review comments there

ACKs for top commit:
  achow101:
    ACK b11a195ef4
  Sjors:
    utACK b11a195ef4
  meshcollider:
    light ACK b11a195ef4

Tree-SHA512: 75ce818d3f03b728b14b12e2d21bd20b7be73978601989cb37ff98254393300d1bb7823281449cd3d9e40756d67d42bd9a46bbdafd2e8baa95aaf2cb1c84549f

test/lint/lint-circular-dependencies.sh

@@ -24,10 +24,6 @@ EXPECTED_CIRCULAR_DEPENDENCIES=(
     "wallet/fees -> wallet/wallet -> wallet/fees"
     "wallet/wallet -> wallet/walletdb -> wallet/wallet"
     "node/coinstats -> validation -> node/coinstats"
-    # Temporary circular dependencies that allow wallet.h/wallet.cpp to be
-    # split up in a MOVEONLY commit. These are removed in #21206.
-    "wallet/receive -> wallet/wallet -> wallet/receive"
-    "wallet/spend -> wallet/wallet -> wallet/spend"
 )
 
 EXIT_CODE=0