Iotagent Opcua Versions Save

• New logic for device provisioning
• Docs alignments

Fix for dynamic provisioning

Fix in configService

• Better handling on envs variables
• Code cleaning
• Better logs in configService
• Updated iotagent-node-lib

Refactoring of data type handling mechanisms

Better handling of array data type coming from OPC UA server

• Bug fixes

Main changes since v2.1.8

• Fix BigInt type handling

Main changes since v2.1.7

• Fix OPC UA Events handling

Main changes since v2.1.6

• Fix for issue #111
• Fix for functional tests
• Support to latest version of iotagent-node-lib