feat: ability to tear down preview environments

**Is your feature request related to a problem? Please describe.**
I'm frustrated that I can not tear down preview environments using the `swa` tool.

Our organization is on a private gitlab installation and due to our insane security policies I can't use the regular `image : registry.gitlab.com/static-web-apps/azure-static-web-apps-deploy` because it's blocked. So I am installing the 'swa` tool in our node images to do deployments to our SWA instance as part of a job in Gitlab's pipeline.

So, I'm trying to setup GitLab's review apps in our project. I would love for when a pull request is closed / merged the `on_stop` job runs and then removes the preview environment created for that particular job. (NB: I create the preview environment during a deploy job using the `swa` tool earlier in the pipeline)

This would also be helpful as the free tier only has a limit of 3 (three) preview environments, so keeping the number of preview environments taken up to the absolute lowest is key.

**Describe the solution you'd like**
A simple tear down flag on the deploy command so that when you run it, it removes a preview environment from your `swa` instance.

## Options

- `-tre, --tear-down-env [environment]`: Removes a preview environment based on the name provided

```
swa deploy --tear-down-env "preview-environment-name"
```

**Describe alternatives you've considered**
The only alternative I can think of is logging into the Azure portal and manually deleting the preview environments.

**Additional context**
No additional context just to saw that I'm so happy you even created the `swa` tool. It's a lifesaver for me already, and I appreciate the continued support and enhancement to this tool and our unique use cases.

Start at the swa deploy command and review how preview environments are created for a named environment. Add a teardown path that accepts the requested environment name and removes that preview environment, then verify that the command works for the GitLab on_stop use case and does not affect other environments.

Written by the indexing model from the issue text.