MdePkg: Support FDT library.

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4392
Add FDT support in EDK2 by submodule 3rd party libfdt
(https://github.com/devicetree-org/pylibfdt/tree/main/libfdt)
and refer to LibcLib implementation by Pedro.

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Zhiguang Liu <zhiguang.liu@intel.com>
Signed-off-by: Benny Lin <benny.lin@intel.com>
Acked-by: Pedro Falcato <pedro.falcato@gmail.com>
Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com>

MdePkg/Library/BaseFdtLib/BaseFdtLib.uni

@@ -0,0 +1,14 @@
+// /** @file
+// Flattened Device Tree Library.
+//
+// Copyright (c) 2023, Intel Corporation. All rights reserved.<BR>
+//
+// SPDX-License-Identifier: BSD-2-Clause-Patent
+//
+// **/
+
+
+#string STR_MODULE_ABSTRACT             #language en-US "Instance of FDT Library"
+
+#string STR_MODULE_DESCRIPTION          #language en-US "This module provides FDT Library implementation."
+