{REST} `az rest` should support polling on asynchronous Azure operations

**Is your feature request related to a problem? Please describe.**
`az rest` should support polling on [asynchronous Azure operations](https://docs.microsoft.com/en-us/azure/azure-resource-manager/management/async-operations).

As difference Resource Providers uses different methods of indicating async operations, there are three possible ways to poll on asynchronous Azure operations

- By response headers
- `Azure-AsyncOperation`
- `Location`
- By response body value
- `provisioningState`

`az rest` should auto-detect it or allow the user to specify the method used for polling.