Expose configuration for Identity Tokens, Certificates, and Security Policies when connecting to a Server

[fgaranda]

The current implementation of the OPC UA/DDS Gateway supports only unsecured and unauthenticated connections to OPC UA Servers. The underlying OPC UA Client provides different mechanisms to configure identity tokens, certificates, and security policies for establishing secure connections to OPC UA Servers. Therefore, the Gateway should provide access to these configuration parameters via XML.

The list of desired configuration parameters may include:

• Username and password
• Client certificate and private Key
• Security mode and security policy URI

See initial feature request for further context.