Kernel: Implement TimeManagement for aarch64

This sets up the RPi::Timer to trigger an interurpt every 4ms using one
of the comparators. The actual time is calculated by looking at the main
counter of the RPi::Timer using the Timer::update_time function.

A stub for Scheduler::timer_tick is also added, since the TimeManagement
code now calls the function.

Kernel/CMakeLists.txt

@@ -503,6 +503,8 @@ else()
         KSyms.cpp
         MiniStdLib.cpp
         StdLib.cpp
+        Time/TimeManagement.cpp
+        TimerQueue.cpp
         UBSanitizer.cpp
         UserOrKernelBuffer.cpp