Add a more complete Teleport Cloud introduction (#12602)
Add a more complete Teleport Cloud introduction (#12602)

* Add a more complete Teleport Cloud introduction

Fixes #11226

- Include more detail about what Teleport Cloud encompasses
- Explain the benefits of Teleport Cloud
- Add Tiles to link to all pages in the /docs/cloud section

* Respond to PR feedback

* Respond to PR feedback
gravitational/teleport,gravitational/teleport,gravitational/teleport,gravitational/teleport,gravitational/teleport,gravitational/teleport