RedfishPkg: DSC and FDF include files for enabling EFI Redfish support

Provide the DSC/FDF include files of edk2 Redfish related
modules and definitions which can be included in platform's
DSC/FDF.

Signed-off-by: Abner Chang <abner.chang@hpe.com>

Cc: Jiaxin Wu <jiaxin.wu@intel.com>
Cc: Siyuan Fu <siyuan.fu@intel.com>
Cc: Fan Wang <fan.wang@intel.com>
Cc: Nickle Wang <nickle.wang@hpe.com>
Cc: Peter O'Hanley <peter.ohanley@hpe.com>
Reviewed-by: Nickle Wang <nickle.wang@hpe.com>

RedfishPkg/RedfishDefines.dsc.inc

@@ -0,0 +1,27 @@
+## @file
+# RedfishPkg DSC include file for [Defines] section of all Architectures.
+#
+# This file can be included to the [Defines] section of a platform DSC file by
+# using "!include RedfishPkg/RedfishDefines.dsc.inc" to set value of
+# flags.
+#
+# These flags can be defined before the !include line, or changed on the command
+# line to enable or disable related feature support.
+#   -D FLAG=VALUE
+#
+# The default value of these flags are:
+#   DEFINE REDFISH_ENABLE = TRUE
+#
+# (C) Copyright 2020 Hewlett Packard Enterprise Development LP<BR>
+#
+#    SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+!ifndef REDFISH_ENABLE
+  #
+  # This flag is to enable or disable the whole Redfish support.
+  #
+  DEFINE REDFISH_ENABLE = TRUE
+!endif
+