RDAP domain expiry check for TLDs that support it

[berthubert]

After discussion with @alarig it emerged that some registries publish through RDAP when a domain is set to expire.
https://data.iana.org/rdap/dns.json has a list of servers
then query the RDAP server with https://rdap.server/domain/domain.com and parse the JSON.
For example: curl https://rdap.publicinterestregistry.org/rdap/domain/skewdb.org
Not all TLDs provide RDAP and many do not publish expiry date, or it might not even be meaningful.