- use `appdatabse.DbInitializer{}` in tests to ensure consistent migrations
- remove protocol's open database functions due to improper
initialization caused by missing node config migration
- introduce `PushNotificationServerConfig` to resolve cyclic dependency
issues
Added a unit test for changing app and wallet DBs passwords.
Refactored geth_backend to simplify and allow wallet db password changing.
Fixed opening database with wrong password.
The only place where appDB is used in wallet is activity,
which refers to `keycards_accounts` table. So a temporary
table `keycards_accounts` is created in wallet db and updated
before each activity query.