PerformancePkg: Remove it

PerformancePkg contains following components:
1. TscTimerLib
2. Dp_App
3. Header files.

#1 has already been deprecated.
#2 can be removed because DpApp was added to ShellPkg.
#3 Header files are not used by DpApp and
   MdeModulePkg/PerformanceLib instances.

In summary, this package is no longer useful.

All related platforms have been updated to remove the references.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Jaben Carsey <jaben.carsey@intel.com>
Cc: Daryl McDaniel <edk2-lists@mc2research.org>
Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>