Add Fleet as a method to deploy Cloudflare WARP client

[dherder]

Summary

The Cloudflare WARP client can be deployed via Fleet on macOS, Windows, and Linux hosts.

Screenshots (optional)

Documentation checklist

• [x] The documentation style guide has been adhered to.
• [x] If a larger change - such as adding a new page- an issue has been opened in relation to any incorrect or out of date information that this PR fixes.
• [ ] Files which have changed name or location have been allocated redirects.