CI: Clean_Test_Server_Images(): harmonize code

- pass parameter directly instead of indirectly via class
- harmonize to svr_id to read through common code in the next commits
- pass images to express which images will be deleted
- refactor function to use "with" for cls_cmd, and return success (or
  not)

ci-scripts/xml_files/container_sa_aerial_quectel.xml

@@ -128,7 +128,8 @@
                 <class>Clean_Test_Server_Images</class>
                 <always_exec>true</always_exec>
                 <desc>Clean Test Images on Test Server</desc>
-                <test_svr_id>0</test_svr_id>
+                <svr_id>0</svr_id>
+                <images>oai-gnb-aerial</images>
         </testCase>
 
 </testCaseList>