Simple server

[viacheslauK]

Brief

Adds a lightweight OPC UA server that publishes an openDAQ device's signals as plain OPC UA variable nodes, skipping the full TMS type/address-space mapping.

• SignalNode: adds a variable node per signal, maps SampleType to OPC UA data type, writes last value + source timestamp.
• GenericServer: builds a device object node in the Objects folder with one variable node per signal, runs a 100 ms background thread to push values, tracks client connect/disconnect, registers an OpenDAQOPCUASimple server capability, and installs read-only access control..