LDAP: Make it possible to extend an attribute map
This commit adds a new option ldap_user_extra_attrs that is unset by
default. When set, the option contains a list of LDAP attributes the LDAP
provider would download and store in addition to the usual set.
The list can either contain LDAP attribute names only, or colon-separated
tuples of LDAP attribute and SSSD cache attribute name. In case only LDAP
attribute name is specified, the attribute is saved to the cache verbatim.
Using a custom SSSD attribute name might be required by environments that
configure several SSSD domains with different LDAP schemas.
Reviewed-by: Simo Sorce <email@example.com>
Reviewed-by: Pavel Březina <firstname.lastname@example.org>