ASG or Autoscaling Group

[migara]

Improve the auto scaling example.

• [x] Retire old asg example
• [x] Improve the new autoscaling example (dynamic deployments controlled via tfvars)
• [x] Rename the example to combined_vmseries_and_autoscale
• [x] Add basic details on what autoscaling is, simple topology and what the end deployment would look like.
• [x] Add a topology diagram
• [x] Explain the steps in the README
• [x] Prerequisites need to be defined in terms of architecture

[sebastianczech]

Estimated workload:

• 0.5 MD - renaming example, improving details in README and adding better topology diagram, without changing code (description of all variables in example I already put while preparing that example)

For future in order to improve example:

• 3 MD - rebuilding and testing code in with approach where everything is controlled by terraform.tfvars and we have for_each loop in main.tf for each resource
• 2 MD - adding additional code to setup Panorama and configuration as a code - then we can use example E2E to setup whole environment ready to generate traffic and trigger autoscaling

[sebastianczech]

Changes prepared in https://github.com/PaloAltoNetworks/terraform-aws-vmseries-modules/pull/299