Add GetConfiguration/SetConfiguration/UploadFile methods

[barnstee]

This is meant to configure the connectivity software. This can include the following configurations:

1. Software lic download
2. Driver loading (e.g. Siemens S7, etc.)
3. Certificate/security settings download
4. Feature config, e.g. store & forward
5. Change management tracking/Logging

Should be accessible through GetConfiguration/SetConfiguration methods.

[barnstee]

For number 3, OPC UA already defines a GDS server push model to upload/provision a certificate.

[barnstee]

We could make this generic (e.g. provide key-value pairs) and move it over to the UA working group.

[barnstee]

GetConfiguration()/SetConfiguration() with key/value pairs. UploadFile() for southbound driver certificates and licensing file.

[barnstee]

Dynamically loading drivers/southbound connectors (number 2 above), this is a nice-to-have feature and most connectivity software load all available drivers all the time and then get instantiated when used.

[barnstee]

This has been added to the V1.1 spec.