build, wallet, doc: Remove BDB

test/functional/wallet_migration.py

@@ -15,7 +15,6 @@ from test_framework.address import (
     script_to_p2sh,
     script_to_p2wsh,
 )
-from test_framework.bdb import BTREE_MAGIC
 from test_framework.descriptors import descsum_create
 from test_framework.key import ECPubKey
 from test_framework.test_framework import BitcoinTestFramework
@@ -33,6 +32,8 @@ from test_framework.wallet_util import (
     generate_keypair,
 )
 
+BTREE_MAGIC = 0x053162
+
 
 class WalletMigrationTest(BitcoinTestFramework):
     def set_test_params(self):