OvmfPkg: Support Tdx measurement in OvmfPkgX64

OvmfPkg: Support Tdx measurement in OvmfPkgX64

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4243

This patch enables Tdx measurement in OvmfPkgX64 with below changes:
1) CC_MEASUREMENT_ENABLE is introduced in OvmfPkgX64.dsc. This flag
   indicates if Intel TDX measurement is enabled in OvmfPkgX64. Its
   default value is FALSE.
2) Include TdTcg2Dxe in OvmfPkgX64 so that CC_MEASUREMENT_PROTOCOL
   is installed in a Td-guest. TdTcg2Dxe is controlled by
   TDX_MEASUREMENT_ENABLE because it is only valid when Intel TDX
   measurement is enabled.
3) OvmfTpmLibs.dsc.inc and OvmfTpmSecurityStub.dsc.inc are updated
   because DxeTpm2MeasureBootLib.inf and DxeTpmMeasurementLib.inf
   should be included to support CC_MEASUREMENT_PROTOCOL.

Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>