monitor: do not check list of rss item with start_date, only consider limit

We can set a specific port-base to use for monitor instance. We can also activate
or desactivate monitor by using parameter "monitor": true in zope or mariadb parameters.

Conflicts:
	stack/erp5/buildout.cfg

Conflicts:
	software/slapos-master/instance-erp5.cfg.in
	software/slapos-master/software.cfg
	stack/erp5/buildout.cfg
	stack/erp5/instance.cfg.in

Conflicts:
	stack/erp5/buildout.cfg

Sorry everyone for this mistake.

Conflicts:
	software/neoppod/software.cfg
	stack/erp5/buildout.cfg
	stack/erp5/instance-erp5-cluster.cfg.in
	stack/erp5/instance-erp5-single.cfg.in
	stack/erp5/instance-zope.cfg.in

This reverts commit f2e57a03.

In order not to conflict with a future integration of NEO in ERP5:
- the input schema has a new parameter for external storages.
- zodb-software-type & zodb is used only for internal storages
  and only ZEO is supported.

NEO logging is also enabled for clients.

Contrary to ERP5, there's no mysql-update service:
- this simplifies the SR
- after reading the MySQL documentation, the automatic use of mysql_upgrade
  is quite frightening:
  « You should always back up your current MySQL installation before performing
  an upgrade. »
  « After running mysql_upgrade, stop the server and restart it so that any
  changes made to the system tables take effect. » (which is currently not done
  by the recipe)
- the future of NEO is an embedded DB like libmysqld