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 <[email protected]>
Cc: Jaben Carsey <[email protected]>
Cc: Daryl McDaniel <[email protected]>
Reviewed-by: Jaben Carsey <[email protected]>

Author: lgao4