Feature Request: Adding list-usage command to disk-encryption-set command group

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

I tried to use the CLI to get a quota for Disk Encryption Sets using `az disk-encryption-set list-usage -l eastus` in a manner similar to how you would check quota usage for VMs or for networks (for example, `az vm list-usage -l eastus`), but the list-usage isn't part of the command group for disk-encryption-set.

The issue faced is that after deploying 50 Disk Encryption Set instances, the subscription limit was hit. However, there's no way to check what the subscription limit is through CLI (to my knowledge), so I figured checking it with CLI could be done the same way you'd check quota usage for VMs, using the list-usage command.

However you get this message:

```
az disk-encryption-set: 'list-usage' is not in the 'az disk-encryption-set' command group. See 'az disk-encryption-set --help'. If the command is from an extension, please make sure the corresponding extension is installed. To learn more about extensions, please visit https://docs.microsoft.com/en-us/cli/azure/azure-cli-extensions-overview
```

**Describe the solution you'd like**

I think it would be nice if the list-usage command could be added to other groups such as disk-encryption-sets. It is very useful to see where you are on quotas and usage without having to use the Portal.

**Describe alternatives you've considered**

I'm not sure if there are other CLI alternatives that could get me the same end goal (being able to see limits for that resource type on the subscription), but I would be open to alternatives if any exist. Thank you!