CodeGen from PR 16453 in Azure/azure-rest-api-specs

Adding Microsoft.Chaos API Version 2021-09-15-preview. (#16453)

* [baseline] Microsoft.Chaos private preview API Version 2021-09-15-preview.

* msft.chaos PublicPreview API 2021-09-15-preview
* Add neccessary readme's from swagger tool branch generation.
* remove artifiact resource from public preview.
* fix static linter issues.

Author: SDKAuto