Add support for defining namespace index in nodesfile

[techmantel]

Please provide us with the following information:

This issue is for a: (mark with an x)

- [ ] bug report -> please search issues before submitting
- [x] feature request
- [ ] documentation issue or request
- [ ] regression (a behavior that used to work and stopped in a new release)

Minimal steps to reproduce

Any log messages given by the failure

Expected/desired behavior

In some cases it would be very useful to be able to define the OPC UA namespace index to be able to simulate PLCs having the user defined tags in a different namespace index than the currently hardcoded ns=3 where all the tags defined in nodesfile are.

OS and Version?

Windows 7, 8 or 10. Linux (which distribution). macOS (Yosemite? El Capitan? Sierra?)

Versions

Mention any other details that might be useful

[luiscantero]

@techmantel thanks for suggesting this. We are evaluating how we can help here best.