enable sitemap tag inside sitemaps (not only in sitemap-index)

[Sammeeey]

Is your feature request related to a problem? Please describe. I have to generate many sitemaps dynamically, because I'm exceeding Googles limit of 50.000 pages per sitemap. But it seems not possible to generate sitemaps which contain sitemaps. The sitemaps tag is only available in sitemap indexes.

Describe the solution you'd like Would be great to have a sitemap field in ISitemapField, which makes clear that this is a sitemap and not a URL.

Thus you could build sitemaps of sitemaps.

Describe alternatives you've considered Just displaying all sitemaps using nexts internal solution