[#54496740] Updates Sequel to 4.6.0

 - Notable changes: 3.46 -> 4.x
  - DB.select and DB.from do not take hash arguments for alias by default, thus we use
    Sequel.as to specify aliases (alternatively you can reenable with the :hash_aliases extension
  - Database#default_schema= is removed. We already set the search_path to schema_name
Use a Sequel extension rather than monkey patching within jdbc database