portSTACK_TYPE is an internal macro defined by the porting layer. This commit
changes all references to StackType_t which is the official type exposed by
FreeRTOS.
This commit refactors the "freertos" component's structure as follows:
- "FreeRTOSConfig.h" related files moved to "./config" directory
- Refactored CMakeLists.txt file in preparation for v10.5.1 upgrade
- Grouped list appends based on component organization
- Removed some unecessarily public "include_dirs"
- Removed FreeRTOS-openocd.c
- uxTopUsedPriority has been added back to tasks.c since v10.4.2
- Thus the workaround in FreeRTOS-openocd.c is no longer needed and can
be removed.