```
Leave wallet/db.{cpp/h} for generic WalletDatabase stuff. The BDB
specific stuff goes into bdb.{cpp/h}
```
Completes backport (5/5) of core [[https://github.com/bitcoin/bitcoin/pull/19290 | PR19290]]:
https://github.com/bitcoin/bitcoin/pull/19290/commits/61c16339da4e80b1320a6296df6d96cd7a84bb4e
Depends on D8614.