💡 A mechanism to retrieve the currently running quick tunnels

**Describe the feature you'd like**
When you startup a quick tunnel, it's difficult to access the current URL for that tunnel. This makes it difficult to create dev scripts using tunnels.

**Describe alternatives you've considered**
Shopify's CLI uses tunnels as part of their development workflow, but the only way it looks like they could accomplish this was from parsing the log stream:
https://github.com/Shopify/cli/blob/f74d9909f4c7ffbc9d7b7a1af17d7cd5f3d8cf8c/packages/plugin-cloudflare/src/tunnel.ts#L207-L210

**Additional context**
As part of multiple applications, I wanted to have a script that would startup a development environment (i.e. `npm dev`) and have that script startup a Cloudflare Quick Tunnel and open the URL in the default web browser. It can be difficult to determine the correct URL to open.