Roadmap for pvAccessCPP vs PVXS

[gilesknap]

When creating generic IOCs based on this image there is an important distinction to be aware of.

We are in the process of eliminating the old pvAccess libraries from our containers in favour of using PVXS.

However at present AreaDetector is still using the old libraries.

At the time of writing there are two base images that you must choose between:

• 7.0.9ec3 - this has PVXS libraries built in but no pvAccessCPP (etc.) - use this for non Areadetector generic IOCs
• 7.0.8ac3 - this has pvAccess submodules compiled in but no PVXS - use this for Areadetector generic IOCs

If you want to add PVXS as well to an Areadetector generic IOC then add this to the Dockerfile:

COPY ibek-support/pvxs/ pvxs
RUN ansible.sh pvxs

In the near future ADCore will be updated to use PVXS for the NDPluginPva and then all generic IOCs may be based upon the latest epics base image. This PR will apply this change areaDetector/ADCore#528.

One final thing! The pvaDriver support module is also still based on pvAccessCPP and at present is not being updated to PVXS. This will still require the 7.0.8ac3 base image for the time being.