Add UID scanner functionality and related infrastructure

- Introduced a new module `uid_scanner` in userspace for managing UID scanning.
- Created a new GitHub Actions workflow for building the `user_scanner`.
- Implemented kernel communication in `throne_comm.c` and `throne_comm.h` to handle user space updates and rescan requests.
- Developed the `uid_scanner` daemon in C to scan user directories and manage UID whitelists.
- Added configuration management for the UID scanner with support for multiple users and auto-scanning.
- Implemented logging and error handling throughout the UID scanning process.
- Created necessary build files for the `user_scanner` JNI integration.
- Added a `.gitignore` file to exclude build artifacts.

kernel/kernel_compat.h

@@ -5,36 +5,6 @@
 #include <linux/version.h>
 #include "ss/policydb.h"
 #include "linux/key.h"
-#include <linux/list.h>
-
-/**
- * list_count_nodes - count the number of nodes in a list
- * @head: the head of the list
- *
- * This function iterates over the list starting from @head and counts
- * the number of nodes in the list. It does not modify the list.
- *
- * Context: Any context. The function is safe to call in any context,
- *          including interrupt context, as it does not sleep or allocate
- *          memory.
- *
- * Return: the number of nodes in the list (excluding the head)
- */
-#if LINUX_VERSION_CODE < KERNEL_VERSION(6, 6, 0)
-static inline __maybe_unused size_t list_count_nodes(const struct list_head *head)
-{
-    const struct list_head *pos;
-    size_t count = 0;
-
-    if (!head)
-        return 0;
-
-    list_for_each(pos, head)
-        count++;
-
-	return count;
-}
-#endif
 
 /*
  * Adapt to Huawei HISI kernel without affecting other kernels ,