uniformly exploit rootdn bind; add support for rootdn bind to backends that didn't have it (ITS#4962)

(ConfigReply) for the error messages.

_db_destroy functions.

that created the PerlInterpreter object (ITS#4751)

Thanks to Alister Winfield for the patch.

use LDAP_SIZELIMIT_EXCEEDED; rework the return values of slap_send_search_entry(); silence a few warnings