asn1: DER format (X.690 ITU-T) and oid support

This module provides functions to decode and encode the distinguished encoding
rules (DER) format as defined in the X.690 ITU-T standard.

See [[derencoder]] and [[derdecoder]] for how to encode or decode values.

This module also provides tools to work with oids. See [[oiddb]] for more info.
