Add necessary files for OPCUA ioc build

[esmith1729]

Description of work

OPCUA IOC module that should be general purpose, for other OPC servers that need an IOC configuration.

OPCUA_01.cmd should be placed in C:\Instrument\Settings\config\[instrument name]\configurations\opcua folder, alongside a private key found on the network shares

To test

• Please confirm that this builds and runs correctly with the OPC PLC on MAPS, and that the OPCUA module looks accurately like other EPICS IOCs (this is my first time porting a new module to EPICS like this).

• You will need to copy the opcua\MAPS_OPCUA\ folder from the non-public shares into your config ...\<NDW###\configurations\ copy and paste the folder there and name it opcua so it can get pickup up by the IOC. Only copy the MAP_OPCUA folder itself and rename it.

• MAPS: Provide support to read pressure values from vacuum PLC IBEX#8586

Acceptance criteria

• The IOC builds and can run properly (it connects to the MAPS PLC and reads values accurately. There should be two TPG-like OPIs displayed (the OPI is called MAPS-OPC-Server

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Code Review

• A copy of the manual has been placed on the shared drive
• Pertitent information has been stored in the wiki
• Does the IOC conform to IBEX standards?
  • PV naming.
  • Disable records
  • Record simulation
  • Finishing touches
• If an OPI has been modified, does it conform to the style guidelines?
• Do the IOC and support module conform to the new build guidelines
• Have the changes been recorded appropriately in a PR for release notes?
• Is the device's flow control setting correct? For most devices flow control should be OFF.

Functional Tests

• IOC responds correctly in:
  • Devsim mode
  • Recsim mode
  • Real device, if available
• Supplementary IOCs (..._0n where n>1) run correctly
• Log files do not report undefined macros (serach for macLib: macro to find instances of macLib: macro [macro name] is undefined...

Final steps

• Update the IOC submodule in the main EPICS repo. See Git workflow page for details.
• Reviewer has merged the associated PR for the release notes

[Tom-Willemsen]

• There's a lot of example code in this PR which makes it a bit tricky to review - could we cut down this IOC to the bits we're actually using? I think probably the entire exampleTop directory can go.
• Please add some documentation on the wiki. I think we probably need two pages:
  • One for OPCUA in general (e.g. write the documentation to help someone who is configuring a new OPCUA device on another instrument). Example topics:
    • How is authentication being handled?
    • Do any settings in the PLC side need adjusting to get communicating properly?
    • Where are instrument-specific configs loaded from (looks like opcua folder in configs area, but please document this)
    • Where are instrument-specific DBs defined
    • Any troubleshooting information you know of - e.g. what errors have you seen during the course of development and how were they resolved?
    • As a supporter / on-call person, what would I need/want to know if I get a call saying communication with an OPCUA server isn't working?
  • One for the MAPS vacuum system in particular, describing the operation/code behind the MAPS vacuum. No need to repeat the generic OPCUA IOC information here, link to the page above, just describe what is specific for MAPS' implementation.
    • As a supporter / on-call person, what would I need/want to know if I get a call saying communication with MAPS' vacuum system isn't working?
  • I think both of these pages are sub-pages under the PLCs section of the docs
• Please add release notes