Native tooling for creating reverse ptr records from a given IPv4 or v6 address

[danimo]

Actual Behavior

When creating reverse pointers, one has to resort to terraform primitives to transform a given IP to a revere transcription for the PTR record. This works for IPv4, but not for IPv6. For v6 ptrs one could resort to external commands, but this would no longer be idempotent.

Expected Behavior

Provide a utility function that accepts a forward IP address as name and produces a PTR record which it forwards to pdns, e.g. name = to_ptr("192.168.1.1"). Another alternative is to provide a dedicated ptr record resource, similar to the Aure DNS Provider.