Review Carto accounts and data source

[ivbeg]

Carto is the SaaS product with spatial datasets uploaded by it's users. A lot of these datasets are public and available from users pages:

• https://connoribbetson.carto.com
• https://serzhilin.carto.com
• https://dinas.carto.co
  and thousands others.

These accounts couldn't be considered as Carto instances since thats users accounts with relatively small number of datasets, less than 100 datasets per account. There is no single point to search and access all datasets, only per account. There is not a lot of metadata available publicly, but it's available via API. Example, https://bfmtv.carto.com/api/v1/viz?types=table

How to add this catalog to the registry ?