squash commits that revert AUTH_LDAP_USER_SEARCH

add missing AUTH_LDAP_USER_SEARCH, removed while modifying....

revert AUTH_LDAP_USER_SEARCH variable that was accidentally removed in netbox-community#931 and change behaviour to requested features in netbox-community#471

remove duplicate AUTH_LDAP_USER_SEARCH variable now and fix this finally, hopefully

configuration/ldap/ldap_config.py

@@ -65,6 +65,10 @@ def _import_group_type(group_type_name):
     'AUTH_LDAP_USER_SEARCH_FILTER', f'({AUTH_LDAP_USER_SEARCH_ATTR}=%(user)s)'
 )
 
+AUTH_LDAP_USER_SEARCH = LDAPSearch(
+    AUTH_LDAP_USER_SEARCH_BASEDN, ldap.SCOPE_SUBTREE, AUTH_LDAP_USER_SEARCH_FILTER
+)
+
 # This search ought to return all groups to which the user belongs. django_auth_ldap uses this to determine group
 # heirarchy.