After reading this discussion, and thanks to @dnutan’s links there I think that to support Lotus Dominio as remote accounts provider we need to change
- NethServer::SSSD Perl library
- sssd configuration
- server manager ldap client helpers, @giacomo already pointed out one of them
- accounts provider configuration wizard in server manager
- configuration of modules that access LDAP directly, like nextcloud, webtop, roundcube, ejabberd, where LDAP query filters are defined for each supported LDAP schema