Add az command to access Azure ResourceHealth status

**Related command**

**Is your feature request related to a problem? Please describe.**

Azure announces maintenances or defects of a service (e.g virtual machine) in the Azure ResourceHeath API endpoint.

Currently, the az cli does not have a command to access this api endpoint and read announcements via cli.

**Describe the solution you'd like**

Please implement a method to access the api endpoint. Basically, this is the method with the az rest implementation:
**Describe alternatives you've considered**

```
az rest --method get --url https://management.azure.com/subscriptions/${ARM_SUBSCRIPTION_ID}/providers/Microsoft.ResourceHealth/availabilityStatuses
```
**Additional context**