PrmPkg: Refactor some PrmLoaderDxe functionality into libraries

This change breaks out two sets of responsibilities in
PrmLoaderDxe into libraries:
  * PE/COFF functions -> PrmPeCoffLib
  * PRM module discovery functions -> PrmModuleDiscoveryLib

This is core infrastructure code for PRM functionality that needs
to be directly reused and tested in other places. At this time,
the primary motivating factor is to use this code in two other
locations:
  1.) Link the functionality into unit testing modules
  2.) Link the functionality into a PRM UEFI application

Cc: Andrew Fish <afish@apple.com>
Cc: Kang Gao <kang.gao@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Michael Kubacki <michael.kubacki@microsoft.com>
Cc: Leif Lindholm <leif@nuviainc.com>
Cc: Benjamin You <benjamin.you@intel.com>
Cc: Liu Yun <yun.y.liu@intel.com>
Cc: Ankit Sinha <ankit.sinha@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
Acked-by: Michael D Kinney <michael.d.kinney@intel.com>
Acked-by: Liming Gao <gaoliming@byosoft.com.cn>
Acked-by: Leif Lindholm <quic_llindhol@quicinc.com>
Reviewed-by: Ankit Sinha <ankit.sinha@intel.com>

PrmPkg/Include/PrmModuleImageContext.h

@@ -0,0 +1,28 @@
+/** @file
+
+  Definitions used internal to the PrmPkg implementation for PRM module image context.
+
+  Copyright (c) Microsoft Corporation
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef PRM_MODULE_IMAGE_CONTEXT_H_
+#define PRM_MODULE_IMAGE_CONTEXT_H_
+
+#include <IndustryStandard/PeImage.h>
+#include <Library/PeCoffLib.h>
+
+#include <PrmExportDescriptor.h>
+
+#pragma pack(push, 1)
+
+typedef struct {
+  PE_COFF_LOADER_IMAGE_CONTEXT          PeCoffImageContext;
+  EFI_IMAGE_EXPORT_DIRECTORY            *ExportDirectory;
+  PRM_MODULE_EXPORT_DESCRIPTOR_STRUCT   *ExportDescriptor;
+} PRM_MODULE_IMAGE_CONTEXT;
+
+#pragma pack(pop)
+
+#endif