Add support for unsupported controls

[nitnelave]

We've run into an issue with a client sending extra controls with their request, that we don't care about but fail the query parsing: lldap/lldap#301

Would there be a way to either add support for the controls, or add a "parse with unsupported controls as an extra return" method?

[inejge]

This crate constructs LDAP client requests, and doesn't parse them (it parses server responses.) Is your issue related to ldap3_proto, perhaps? Anyway, I can't find "Unsupported control oid" anywhere in lldap sources, so I can't check.

[nitnelave]

Oops, sorry, the ldap3_proto crate is in a repo also named ldap3, so I got confused.