New test script for scaling vSGs on PODs with a specified count of vSGs to be created

Create a new script for Scaling vSGs on PODs 

-> script takes scale_count variable which shows the number of vSGs to create.

-> After creating each vSG, it validates the creation of instances in XOS and also

    the data plane instance creations(including container creations)

->script auto generates the required parameters to create subscribers and volt tenants

-> Input file, contains the start of `s_tag`, `c_tag` and `service_specific_id`