KAR-696 Deploy ONLY Python Dish Structure Manager with DishManager updates

Dish LMC has been incrementally ported to Python. This change features the complete removal of C++ LMC devices in our deployment (NB: the code files still need to be purged). Notable changes include:

• Dockerfile update to remove C++ code compilation (and conform to pattern across Python repositories)
• Pipeline improvements:
  • Makefile k8s chart parameters (flags) updated
  • Only one acceptance test job in test stage
• README updated to reflect the latest state of DISH LMC and updated flags
• Charts updated to use latest version of software dependencies
• General test improvements:
  • Use of fixtures (notably event callbacks) are scoped for the tests to prevent unintended consequences