Integrate with DataCatalogs.ru

[ivbeg]

Add integration of Awesome Opendata Rus with DataCatalogs.ru Airtable database.
Right now it's separated entities without sync.
We need a script linked with GitHub action to extract list of data catalogs from Airtable read-only API and to generate markdown file.

Probably we shouldn't rewrite primary list and to generate datasets.md file linked with README.md file.

Any ideas welcome. If you would like to contribute, ask me for Airtable database key.