OvmfPkg/UefiCpuPkg/UefiPayloadPkg: Rename VmgExitLib to CcExitLib

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4123

VmgExitLib once was designed to provide interfaces to support #VC handler
and issue VMGEXIT instruction. After TDVF (enable TDX feature in OVMF) is
introduced, this library is updated to support #VE as well. Now the name
of VmgExitLib cannot reflect what the lib does.

This patch renames VmgExitLib to CcExitLib (Cc means Confidential
Computing). This is a simple renaming and there is no logic changes.
After renaming all the VmgExitLib related codes are updated with
CcExitLib. These changes are in OvmfPkg/UefiCpuPkg/UefiPayloadPkg.

Cc: Guo Dong <guo.dong@intel.com>
Cc: Sean Rhodes <sean@starlabs.systems>
Cc: James Lu <james.lu@intel.com>
Cc: Gua Guo <gua.guo@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: James Lu <james.lu@intel.com>
Reviewed-by: Gua Guo <gua.guo@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>

UefiCpuPkg/Library/CcExitLibNull/CcExitLibNull.inf

@@ -0,0 +1,28 @@
+## @file
+#  CcExit Base Support Library.
+#
+#  Copyright (C) 2020, Advanced Micro Devices, Inc. All rights reserved.<BR>
+#  Copyright (c) 2020 - 2022, Intel Corporation. All rights reserved.<BR>
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = CcExitLibNull
+  MODULE_UNI_FILE                = CcExitLibNull.uni
+  FILE_GUID                      = 3cd7368f-ef9b-4a9b-9571-2ed93813677e
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = CcExitLib
+
+[Sources.common]
+  CcExitLibNull.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  UefiCpuPkg/UefiCpuPkg.dec
+
+[LibraryClasses]
+  BaseLib
+