message: Add `Deref` for `QuerierWrapper` CHANGELOG entry
diff: - Deprecate `InitResult`, `HandleResult`, `MigrateResult` and `QueryResult` in
  order to make error type explicit an encourage migration to custom errors.
  +- Implement `Deref` for `QuerierWrapper`, such that `QuerierWrapper` behaves
  + like a smart pointer to `Querier` allowing you to access `Querier` methods
  + directly.
  ## 0.12.0 (2020-11-19)
  