new: usr: "Add code paths to fully support PRIVATEDNS and PRIVATEOID keys"

Added support for PRIVATEDNS and PRIVATEOID key usage. Added PRIVATEOID
test algorithms using the assigned OIDs for RSASHA256 and RSASHA512.

Added code to support proposed DS digest types that encode the PRIVATEDNS
and PRIVATEOID identifiers at the start of the digest field of the DS record.
This code is disabled by default.

Closes #3240

Merge branch '3240-add-privatedns-and-privateoid-support' into 'main'

See merge request isc-projects/bind9!10341