ArmVirtPkg/PlatformCI: factor out reusable PlatformBuildLib.py

In order to reduce the amount of code duplication, refactor the
PlatformBuild.py script that builds ArmVirtQemu.dsc into a reusable
PlatformBuildLib.py containing most of the bits and pieces, and a small
QemuBuild.py which is specific to the DSC in question.

Suggested-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Michael Kubacki <michael.kubacki@microsoft.com>

ArmVirtPkg/PlatformCI/QemuBuild.py

@@ -0,0 +1,31 @@
+# @file
+# Script to Build OVMF UEFI firmware
+#
+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+##
+import os
+import sys
+
+sys.path.append(os.path.dirname(os.path.abspath(__file__)))
+from PlatformBuildLib import SettingsManager
+from PlatformBuildLib import PlatformBuilder
+
+    # ####################################################################################### #
+    #                                Common Configuration                                     #
+    # ####################################################################################### #
+class CommonPlatform():
+    ''' Common settings for this platform.  Define static data here and use
+        for the different parts of stuart
+    '''
+    PackagesSupported = ("ArmVirtPkg",)
+    ArchSupported = ("AARCH64", "ARM")
+    TargetsSupported = ("DEBUG", "RELEASE", "NOOPT")
+    Scopes = ('armvirt', 'edk2-build')
+    WorkspaceRoot = os.path.realpath(os.path.join(
+        os.path.dirname(os.path.abspath(__file__)), "..", ".."))
+
+    DscName = os.path.join("ArmVirtPkg", "ArmVirtQemu.dsc")
+
+import PlatformBuildLib
+PlatformBuildLib.CommonPlatform = CommonPlatform