MdeModulePkg: Add BootDiscoveryPolicyUiLib.

This library extends Boot Maintenance Menu and allows to select
Boot Discovery Policy. When choice is made BootDiscoveryPolicy
variable is set. Platform code can use this variable to decide
which class of device shall be connected.

Signed-off-by: Grzegorz Bernacki <gjb@semihalf.com>
Reviewed-by: Zhichao Gao <zhichao.gao@intel.com>
Reviewed-by: Sunny Wang <sunny.wang@arm.com>

MdeModulePkg/Library/BootDiscoveryPolicyUiLib/BootDiscoveryPolicyUiLib.inf

@@ -0,0 +1,52 @@
+## @file
+#  Library for BDS phase to use Boot Discovery Policy
+#
+#  Copyright (c) 2021, ARM Ltd. All rights reserved.<BR>
+#  Copyright (c) 2021, Semihalf All rights reserved.<BR>
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = BootDiscoveryPolicyUiLib
+  MODULE_UNI_FILE                = BootDiscoveryPolicyUiLib.uni
+  FILE_GUID                      = BE73105A-B13D-4B57-A41A-463DBD15FE10
+  MODULE_TYPE                    = DXE_DRIVER
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = NULL|DXE_DRIVER UEFI_APPLICATION
+  CONSTRUCTOR                    = BootDiscoveryPolicyUiLibConstructor
+  DESTRUCTOR                     = BootDiscoveryPolicyUiLibDestructor
+#
+# The following information is for reference only and not required by the build tools.
+#
+#  VALID_ARCHITECTURES           = IA32 X64 AARCH64
+#
+
+[Sources]
+  BootDiscoveryPolicyUiLib.c
+  BootDiscoveryPolicyUiLibStrings.uni
+  BootDiscoveryPolicyUiLibVfr.Vfr
+
+[Packages]
+  MdePkg/MdePkg.dec
+  MdeModulePkg/MdeModulePkg.dec
+
+[LibraryClasses]
+  DevicePathLib
+  BaseLib
+  UefiRuntimeServicesTableLib
+  UefiBootServicesTableLib
+  DebugLib
+  HiiLib
+  UefiLib
+  BaseMemoryLib
+
+[Guids]
+  gBootDiscoveryPolicyMgrFormsetGuid
+
+[Pcd]
+  gEfiMdeModulePkgTokenSpaceGuid.PcdBootDiscoveryPolicy  ## PRODUCES
+
+[Depex]
+  gEfiHiiDatabaseProtocolGuid AND gPcdProtocolGuid