{AKS} Refactor 7th part of the create sub-command in aks-preview module

[FumingZhang]

---

This checklist is used to make sure that common guidelines for a pull request are followed.

• Add back-compatibility support for --node-zones and --enable-vmss
  • In aks-preview, the parameter form of option --node-zones is node_zones, while this is --zones (option form) and zones (parameter form) in azure-cli.
  • In ask-preview, we have a deprecated option --enable-vmss, which is used to change the value of another option --vm-set-type.

Unit Test Coverage:

• "covered_lines": 358,
• "num_statements": 384,
• "percent_covered": 93.22916666666667,
• "missing_lines": 26,
• "excluded_lines": 0

General Guidelines

• Have you run azdev style <YOUR_EXT> locally? (pip install azdev required)
• Have you run python scripts/ci/test_index.py -q locally?

For new extensions:

• My extension description/summary conforms to the Extension Summary Guidelines.

About Extension Publish

There is a pipeline to automatically build, upload and publish extension wheels.
Once your PR is merged into master branch, a new PR will be created to update src/index.json automatically.
The precondition is to put your code inside this repo and upgrade the version in the PR but do not modify src/index.json.

[yonzhan]

AKS