We need a way to signal that a DB transaction should be rolled back
because its changes were a dry-run only. We add a new specific error for
that case so the automatic rollback on error in the walletdb.View and
walletdb.Update comes to play. But we can still return the result of a
dry-run where we need to by inspecting for this specific error.
This commit implements a new namespaced db package which is intended to
be used be wallet and any sub-packages as its data storage mechanism.
- Key/value store
- Namespace support
- Allows multiple packages to have their own area in the database without
worrying about conflicts
- Read-only and read-write transactions with both manual and managed modes
- Nested buckets
- Supports registration of backend databases
- Comprehensive test coverage
