Separate creation and upload in the CLI

[kytta]

First off, thanks for making smokeshow, it's a game changer for quick website previews and coverage reporting :)

I have the following use case which would be nice to have implemented in the smokeshow CLI:

1. I create a smokeshow site and get its URL
2. I build a static website with the URL as base
   • my SSG prefers having "full"-absolute (https://example.com/some/page) rather than "semi"-absolute (/some/page) URLs
3. I then upload the built site to the already pre-defined URL

This is already achievable with direct API requests, but I really like the UX of uvx smokeshow upload, so it would be nice to add create as a possible subcommand. Here's how I imagine it:

$ uvx smokeshow create
{
    "message": "New site created successfully",
    "secret_key": "foobarbaz",
    "site_creation": "2025-01-20T07:38:05.048Z",
    "site_expiration": "2026-01-20T07:38:05.048Z",
    "sites_created_24h": 0,
    "upload_expiration": "2025-01-20T08:38:05.048Z",
    "url": "https://smokeshow.helpmanual.io/quux/"
}

$ uvx smokeshow upload --url "https://smokeshow.helpmanual.io/quux/" --secret-key "foobarbaz" my/cool/site
uploading 42 files...