Support for LDAP field aggregations / modifications

For some wiki fields I would need to concatenate several LDAP fields (e.g address = street + city + ...) so I would like to be able to concatenate them.

I have also the weird case that first and last name are in all caps in my LDAP. So the coolest thing would be, that I can specify a regex or handler that transforms whatever comes from LDAP.

The same syntax as used in userPageName property could be used to achieve that.

See also: https://forum.xwiki.org/t/ldap-how-to-aggregate-transform-ldap-fields/8246/2