LDAP scope definitions
Originally amended on #5489 (closed), but here filed as dedicated issue (because #5489 (closed) is not only about scope and also because the comment on #5489 (closed) sems to be lost).
ldap_authentication defines
scope = {
'base': ldap3.BASE,
'onelevel': ldap3.LEVEL,
'subtree': ldap3.SUBTREE,
}[scope]
but RFC2255 says:
scope = "base" / "one" / "sub"