feat: Added rt_interrupt_context* family for nested interrupt handling

These changes introduce the rt_interrupt_context family, providing a
mechanism for managing nested interrupts. The context management
ensures proper storage and retrieval of interrupt states, improving
reliability in nested interrupt scenarios by enabling context tracking
across different interrupt levels. This enhancement is essential for
platforms where nested interrupt handling is crucial, such as in real-
time or multi-threaded applications.

Changes:
- Defined rt_interrupt_context structure with context and node fields
  in `rtdef.h` to support nested interrupts.
- Added rt_slist_pop function in `rtservice.h` for simplified node
  removal in singly linked lists.
- Declared rt_interrupt_context_push, rt_interrupt_context_pop, and
  rt_interrupt_context_get functions in `rtthread.h` to manage the
  interrupt/exception stack.
- Modified AArch64 CPU support in `cpuport.h` to include
  rt_hw_show_register for debugging registers.
- Refactored `_rt_hw_trap_irq` in `trap.c` for context-aware IRQ
  handling, with stack push/pop logic to handle nested contexts.
- Implemented interrupt context push, pop, and retrieval logic in
  `irq.c` to manage context at the CPU level.

Signed-off-by: Shell <smokewood@qq.com>

include/rtthread.h

@@ -713,6 +713,10 @@ rt_err_t  rt_device_control(rt_device_t dev, int cmd, void *arg);
 void rt_interrupt_enter(void);
 void rt_interrupt_leave(void);
 
+void rt_interrupt_context_push(rt_interrupt_context_t this_ctx);
+void rt_interrupt_context_pop(void);
+void *rt_interrupt_context_get(void);
+
 /**
  * CPU object
  */