[dev] when host set to localhost, spin up trycloudflared endpoint

[EverlastingBugstopper]

devs should be able to test workers on something that runs on their local machine, let's use trycloudflared

[GregBrimble]

If it's any help, I have a complete example of using cloudflared with wrangler dev which automatically pulls in the tunnel host.

Specifically, index.js is the most interesting bit: it starts the cloudflared tunnel, inspects the Prometheus metrics endpoint and grabs the hostname, and then starts the wrangler dev --host ${hostname} process.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.