Add an option to open Database and StateDB as a secondary DB

[shuse2]

Description

Add option to open Database and StateDB as a secondary DB.
catchup method should be added for secondary db which runs in background thread.
If this function is called for the non-secondary DB, it should throw error.

Motivation

During migration or running third party command, it would be nice to be able to read the database from different process

Acceptance Criteria

• Add test for secondary db case in node.js