slapos_core: use distribute cache for sessions

This prevents to break captcha.

master/bt5/slapos_erp5/PathTemplateItem/portal_caches/erp5_session_cache/distributed_ram_cache.xml

+<?xml version="1.0"?>
+<ZopeData>
+  <record id="1" aka="AAAAAAAAAAE=">
+    <pickle>
+      <global name="Distributed Ram Cache" module="erp5.portal_type"/>
+    </pickle>
+    <pickle>
+      <dictionary>
+        <item>
+            <key> <string>categories</string> </key>
+            <value>
+              <tuple>
+                <string>specialise/portal_memcached/default_memcached_plugin</string>
+              </tuple>
+            </value>
+        </item>
+        <item>
+            <key> <string>id</string> </key>
+            <value> <string>distributed_ram_cache</string> </value>
+        </item>
+        <item>
+            <key> <string>int_index</string> </key>
+            <value> <int>-1</int> </value>
+        </item>
+        <item>
+            <key> <string>portal_type</string> </key>
+            <value> <string>Distributed Ram Cache</string> </value>
+        </item>
+        <item>
+            <key> <string>title</string> </key>
+            <value> <string>distributed_ram_cache</string> </value>
+        </item>
+      </dictionary>
+    </pickle>
+  </record>
+</ZopeData>

master/bt5/slapos_erp5/bt/template_path_list

 portal_alarms/slapos_check_duplicated_software_instance
 portal_alarms/slapos_check_security_uid
 portal_alarms/slapos_erp5_cleanup_active_process
-portal_alarms/slapos_erp5_cleanup_business_template
\ No newline at end of file
+portal_alarms/slapos_erp5_cleanup_business_template
+portal_caches/erp5_session_cache/distributed_ram_cache
\ No newline at end of file