Add pull image with tag prefix and XML

After the parent commit, the registry might contain prefixed images.
This commit adds the functionality to pull such prefixed image. Since we
rename the pulled image (to have a consistent name, from whichever
registry we might pull), remove the prefix as well so that it can be
used with other CI functionality (remove image, use in test, ...)

Examples for renaming:
- pull from internal_registry for x86
  internal_registry/oai-gnb:branchA => oai-ci/oai-gnb:branchA
- pull from internal registry for ARM with "arm_" prefix
  internal_registry/oai-gnb:arm_branchA => oai-ci/oai-gnb:branchA
- pull from x86 other registry (e.g., openshift)
  openshift/namespace/oai-gnb:branchA => oai-ci/oai-gnb:branchA

ci-scripts/main.py

@@ -395,13 +395,14 @@ def ExecuteActionWithParam(action):
 			# Do not pull or remove images when running locally. User is supposed to handle image creation & cleanup
 			return True
 		svr_id = test.findtext('svr_id')
+		tag_prefix = test.findtext('tag_prefix') or ""
 		images = test.findtext('images').split()
 		# hack: for FlexRIC, we need to overwrite the tag to use
 		tag = None
 		if len(images) == 1 and images[0] == "oai-flexric":
 			tag = CONTAINERS.flexricTag
 		if action == "Pull_Local_Registry":
-			success = CONTAINERS.Pull_Image_from_Registry(HTML, svr_id, images, tag=tag)
+			success = CONTAINERS.Pull_Image_from_Registry(HTML, svr_id, images, tag=tag, tag_prefix=tag_prefix)
 		if action == "Clean_Test_Server_Images":
 			success = CONTAINERS.Clean_Test_Server_Images(HTML, svr_id, images, tag=tag)
 
@@ -421,9 +422,10 @@ def ExecuteActionWithParam(action):
 		success = cls_oaicitest.Custom_Script(HTML, node, script, command_fail)
 
 	elif action == 'Pull_Cluster_Image':
+		tag_prefix = test.findtext('tag_prefix') or ""
 		images = test.findtext('images').split()
 		node = test.findtext('node')
-		success = CLUSTER.PullClusterImage(HTML, node, images)
+		success = CLUSTER.PullClusterImage(HTML, node, images, tag_prefix=tag_prefix)
 
 	else:
 		logging.warning(f"unknown action {action}, skip step")