update HMM modules to conform to ldsCtrlEst protocol

[awillats]

• change folder structure
  for:
• hmm
• rtxi_hmm_decoder
• rtxi_hmm_generator
• change name capitalization

[awillats]

these also need relevant README

[awillats]

README is much better. Core module now builds with a simple CMakeLists.txt (from a CMake tutorial rather than MBolus's CMake template).

For now this issue will be paused while i focus on documentation