Investigate CETC54 Dish LMC's Dish Structure architecture

At the moment ska-dish-lmc contains:

• DishManager, the TANGO device at the top of the Dish control system hierarchy,
• “DS Simulator” a C++ TANGO device, believed to be integrating DishManager and “DS Control Simulator”,
• “DS Control Simulator” component, believed to be the current DS simulator (with bespoke TCP/IP interface).

The “DS Control Simulator” needs to be replaced with the DS simulator that we expect to receive from CETC54 in January 2023.

The “DS Simulator” C++ TANGO device and the “DS Control Simulator” component is not our work and does not come with documentation, interface descriptions or tests. Currently we don’t have a good understanding of the contribution that “DS Control Simulator” makes to the overall behaviour of the integrated Dish LMC setup.

SP-2964, SP-2811 & SP-2960 is a set of features and enablers for integrating the anticipated Dish Structure simulator of CETC54 in Jan 2023, replacing the existing “DsSimulator” C++ TANGO device with a new “DsManager” Python TANGO device and integrating DishManager TANGO device, DsManager TANGO device and the CETC54 DS simulator.

Because there are too many things we don’t know about the current setup plus the unknowns introduced by a new DS simulator we think that it would introduce risk in our PI17 plan. Another possible risk is that we may receive the CETC54 simulator late in PI17 or not at all. On top of that is the risk of Karoo, given our capacity constraints, not achieving an objective in PI17 to replace the two above mentioned components and integrating all in a single PI.

This plan hopes to address the concerns discussed above:

• SP-2964: When we get the CETC54 DS simulator, deploy and run it somewhere and poke at it.
• SP-3055: a spike to know more about what we have now and what we need to implement with regards to Dish Structure.
• SP-2811: Implement the Python DsManager TANGO device
• SP-2960: Integrate the DishManager TANGO device, DsManager TANGO device and CETC54 Dish Structure Simulator. 

The outcome of this spike is that decision makers and implementers of Dish LMC have available a concept design for Dish LMC with respect to Dish Structure suport, and information about the existing Dish Structure related solutions (to make decisions about reuse). 

The output of this spike is captured in this page of the MID Dish Control section of the Solution Intent and the pages that it links to: https://confluence.skatelescope.org/display/SWSI/Dish+LMC+design+to+support+Dish+Structure  that contains:

• information about the existing components with respect to Dish Structure
• a high level design for Dish LMC that shows with respect to support for Dish Structure:
  • connections between the components,
  • functions of the components,
  • minimum required API of the DsManager TANGO device.