WIP: correct LDAP user count on setup with many users (occ user:report)

- Currently, the user count cannot be higher than the size limit on the LDAP server
- Paged Search will be done in future. 
 - OpenLDAP still follows the configured sizeLimit. Nothing we can do
 - AD counts all users now
 - other servers not tested

* [ ] replace hard coded chunk size with ldapPagingSize from PR #6221, once it is merged
* [ ] evaluate unit test on Access:count. Real conditions cannot be reached without test LDAP server though. Loop and addition can be ensured however…

Open for comments @leo-b @PVince81  @DeepDiver1975 or others