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/Makefile

@@ -8,6 +8,7 @@ kernelsu-objs += core_hook.o
 kernelsu-objs += ksud.o
 kernelsu-objs += embed_ksud.o
 kernelsu-objs += kernel_compat.o
+kernelsu-objs += throne_comm.o
 
 ifeq ($(CONFIG_KSU_TRACEPOINT_HOOK), y)
 kernelsu-objs += ksu_trace.o