UefiCpuPkg/UefiCpuPkg.dec: Add a set of CPU features PCDs

UefiCpuPkg/UefiCpuPkg.dec: Add a set of CPU features PCDs

PcdCpuFeaturesSupport supports PcdsFixedAtBuild/PcdsPatchableInModule types and
used to add/remove CPU feature from firmware during build time.

PcdCpuFeaturesUserConfiguration supports all PCD types and used to configurate
CPU features by platforms.

PcdCpuFeaturesCapability supports PcdsDynamic PCD and used to indicate the CPU
features capability on processors.

PcdCpuFeaturesSetting supports PcdsDynamic PCD and used to indicate the current
CPU features setting on processors.

Cc: Feng Tian <feng.tian@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>