Everywhere: Move global Kernel pattern code to Kernel/Library directory

This has KString, KBuffer, DoubleBuffer, KBufferBuilder, IOWindow,
UserOrKernelBuffer and ScopedCritical classes being moved to the
Kernel/Library subdirectory.

Also, move the panic and assertions handling code to that directory.

Kernel/Arch/x86_64/Interrupts.cpp

@@ -15,7 +15,7 @@
 #include <Kernel/Interrupts/SharedIRQHandler.h>
 #include <Kernel/Interrupts/SpuriousInterruptHandler.h>
 #include <Kernel/Interrupts/UnhandledInterruptHandler.h>
-#include <Kernel/Panic.h>
+#include <Kernel/Library/Panic.h>
 #include <Kernel/PerformanceManager.h>
 #include <Kernel/Sections.h>
 #include <Kernel/Security/Random.h>