Show Broken Links service

Read one website's Broken Links Checker settings. The id is the website's Broken Links Checker service id: read it from the `site_preset_broken_link` include of a website (`GET /api/public/v1/sites/{site}?include=site_preset_broken_link`, which also carries the global configuration the website uses) or from `meta.updated` of "Assign websites to a Broken Links configuration". Response attributes: `status` (enabled, disabled - a paused website can still be scanned on demand), `schedule` (the schedule inherited from the configuration), `max_pages` (the page cap), `excluded` (object with `url_patterns` and `source_types` arrays, what discovery leaves out), `scan_status`, `last_scan_at`, `issues_count`, `broken_links_count`, `mixed_content_count`, `pages_scanned` (the results of the last scan), `last_request`, `next_request` (null while the website is paused) and the timestamps. The `preset` relationship carries the global configuration this website uses (canonical shape, its own nested `schedule`), included by default. A website that was never assigned a configuration has no Broken Links Checker service. A service of another organization answers 404.