MdeModulePkg: Duplicate BaseRngLibTimerLib to MdeModulePkg

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4504

The BaseRngLibTimerLib allows to generate number based on a timer.
This mechanism allows to have a basic non-secure implementation
for non-production platforms.
To bind and identify Random Number Generators implementations with
a GUID, an unsafe GUID should be added. This GUID cannot be added
to the MdePkg unless it is also added to a specification.

To keep the MdePkg self-contained, copy the BaseRngLibTimerLib to
the MdeModulePkg. This will allow to define an unsafe Rng GUID
in a later patch in the MdeModulePkg.

The MdePkg implementation will be removed later. This allows to give
some time to platform owners to switch to the MdeModulePkg
implementation.

Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Kun Qin <kun.qin@microsoft.com>

MdeModulePkg/MdeModulePkg.dsc

@@ -345,6 +345,7 @@
   MdeModulePkg/Library/BaseBmpSupportLib/BaseBmpSupportLib.inf
   MdeModulePkg/Library/DisplayUpdateProgressLibGraphics/DisplayUpdateProgressLibGraphics.inf
   MdeModulePkg/Library/DisplayUpdateProgressLibText/DisplayUpdateProgressLibText.inf
+  MdeModulePkg/Library/BaseRngLibTimerLib/BaseRngLibTimerLib.inf
 
   MdeModulePkg/Universal/BdsDxe/BdsDxe.inf
   MdeModulePkg/Application/BootManagerMenuApp/BootManagerMenuApp.inf