Kernel: Decouple Intel HDA interrupt handling from controller

The driver would crash if it was unable to find an output route, and
subsequently the destruction of controller did not invoke
`GenericInterruptHandler::will_be_destroyed()` because on the level of
`AudioController`, that method is unavailable.

By decoupling the interrupt handling from the controller, we get a new
refcounted class that correctly cleans up after itself :^)

Kernel/CMakeLists.txt

@@ -47,6 +47,7 @@ set(KERNEL_SOURCES
     Devices/Audio/IntelHDA/Codec.cpp
     Devices/Audio/IntelHDA/Controller.cpp
     Devices/Audio/IntelHDA/Format.cpp
+    Devices/Audio/IntelHDA/InterruptHandler.cpp
     Devices/Audio/IntelHDA/Stream.cpp
     Devices/Audio/Management.cpp
     Devices/BlockDevice.cpp