API for deploying by URL

Hi deno team!

I really, really _love_ the fact that you've built the ability to deploy through a script hosted on the web!

As much as I love git, I don't think it's necessarily the right _primitive_ for deploying web applications, since git clones take a non-trivial amount of time and serves as a minimum latency floor for our iteration cycles. Static assets, on the other hand, feels like a much better primitive since it _is_ the de-facto primitive of the web, and has minimal latency overhead for propagating updates.

That said, one thing I would love to see is the ability to hook into deno deploy's ability to create deployments using a script, through some kind of unofficial API. I see that right now, this is done through the following API call:

```
await fetch("https://dash.deno.com/api/projects/_redacted_/deployments_stream", {
"headers": {
"authorization": "Bearer _redacted_",
"content-type": "application/json",
},
"body": "{\"url\":\"https://_redacted_\",\"production\":true}",
"method": "POST",
});
```

I can already call this API outside of the Deno deploy dashboard, but the fact that there's no way to get issued a persistent authorization token makes the usage rather awkward, as I'd have to deal with the fact that my dashboard token can expire, and manually refresh it from time to time.

Would you please consider the ability to issue an API token from the dashboard to allow other tools to leverage Deno deploy more conveniently? No need to offer any guarantee of API stability, given the early experimental state of the service itself. This could totally stay a use-at-your-own-risk type of thing for the foreseeable future.

Thanks!

Start by reviewing the dashboard flow and the deployments_stream endpoint described in the issue, including how the current dashboard authorization token is issued and expires. Done means a user can issue a persistent token from the dashboard and use it to trigger URL-based deployments without manually refreshing an expiring dashboard token.

Written by the indexing model from the issue text.