Kernel: Add base support for VirtRNG (VirtIO based Hardware RNG)

This is a very basic implementation that only requests 4096 bytes
of entropy from the host once, but its still high quality entropy
so it should be a good fix for #4490 (boot-time entropy starvation)
for virtualized environments.

Co-authored-by: Sahan <sahan.h.fernando@gmail.com>

Kernel/CMakeLists.txt

@@ -223,6 +223,7 @@ set(KERNEL_SOURCES
     VirtIO/VirtIO.cpp
     VirtIO/VirtIOConsole.cpp
     VirtIO/VirtIOQueue.cpp
+    VirtIO/VirtIORNG.cpp
     VM/AnonymousVMObject.cpp
     VM/ContiguousVMObject.cpp
     VM/InodeVMObject.cpp