- Refactored AVR8 constructor, moving TDF construction to the TargetControllerComponent

- The `TargetControllerComponent` now resolves the target via the new generated mapping approach
- Added `TargetDescriptionFile` derived class
- Removed obsolete JSON map processing code
- Other bits of refactoring and tidying

src/Targets/CMakeLists.txt

@@ -10,4 +10,5 @@ target_sources(
         ${CMAKE_CURRENT_SOURCE_DIR}/Microchip/AVR/AVR8/TargetDescription/TargetDescriptionFile.cpp
         ${CMAKE_CURRENT_SOURCE_DIR}/Microchip/AVR/AVR8/OpcodeDecoder/Decoder.cpp
         ${CMAKE_CURRENT_SOURCE_DIR}/RiscV/RiscV.cpp
+        ${CMAKE_CURRENT_SOURCE_DIR}/RiscV/TargetDescription/TargetDescriptionFile.cpp
 )