Add OPC-UA simple synchronous client extension.

This extension uses python-opcua to growse server nodes, and generates runtime C code that use open62541.
- python-opcua must be available in python path (i.e. "import opcua" must succeed). Can be installed from pypi with "python2 -m pip install opcua --user" .
- at build time, open62541 is expected to be build in "open62541" directory, aside "beremiz" directory.

     1

{

     2

    "ID": "wamptest", 

     3

    "active": true, 

     4

    "protocolOptions": {

     5

        "autoPingInterval": 60, 

     6

        "autoPingTimeout": 20

     7

    }, 

     8

    "realm": "Automation", 

     9

    "url": "ws://127.0.0.1:8888"

    10

}