MdeModulePkg: Add sample help information for HelloWorld application.

Since Shell supports finding help information from resource section
of application image. We enhance the HelloWorld to add help information
string. After the HelloWorld are loaded in system the help string will
be stored in resource section of the application image.

Cc: Feng Tian <feng.tian@intel.com>
Cc: Jaben Carsey <jaben.carsey@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Qiu Shumin <shumin.qiu@intel.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

MdeModulePkg/Application/HelloWorld/HelloWorldStr.uni

@@ -0,0 +1,27 @@
+// /** @file
+// Sample UEFI Application Reference EDKII Module.
+//
+// This is a sample shell application that will print "UEFI Hello World!" to the
+// UEFI Console based on PCD setting.
+//
+// It demos how to use EDKII PCD mechanism to make code more flexible.
+//
+// Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>
+//
+// This program and the accompanying materials
+// are licensed and made available under the terms and conditions of the BSD License
+// which accompanies this distribution. The full text of the license may be found at
+// http://opensource.org/licenses/bsd-license.php
+// THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+// WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+//
+// **/
+
+/=#
+
+#langdef en-US "English"
+
+#string STR_HELLO_WORLD_HELP_INFORMATION        #language en-US ""
+".TH HelloWorld 0 "Displays a \"UEFI Hello World!\" string."\r\n"
+".SH NAME\r\n"
+"HelloWorld application.\r\n"