Kernel: Move ProcFS related overrides in Process to ProcessProcFSTraits

This allows us to 1) let go of the Process when an inode is ref'ing for
ProcFSExposedComponent related reasons, and 2) change our ref/unref
implementation.

Kernel/CMakeLists.txt

@@ -182,6 +182,7 @@ set(KERNEL_SOURCES
     ProcessExposed.cpp
     ProcessSpecificExposed.cpp
     ProcessGroup.cpp
+    ProcessProcFSTraits.cpp
     RTC.cpp
     Random.cpp
     Scheduler.cpp