[IMP] maintenance_service_http_monitoring : speed up KO confirmation

The previous design required two passes of the 10-minute sweep before a
maintenance request was created, so an outage took at least ~10 extra
minutes (up to 20) to be reported.

Split the monitoring into two crons with distinct responsibilities:

- the 10-minute sweep only discovers outages, flags the KO streak via
  ``http_first_ko_at`` and auto-resolves recovered services;
- a new 2-minute confirmation cron re-checks only the flagged services
  and creates a request once the service has been continuously KO for
  ``HTTP_KO_CONFIRMATION_DELAY`` (lowered from 5 to 2 minutes).

This keeps the transient-outage filter while removing the extra sweep
latency. Services already under an open request are skipped by the
confirmation cron and remain handled by the sweep.

maintenance_service_http_monitoring/data/cron.xml

@@ -8,6 +8,14 @@
         <field name="interval_number">10</field>
         <field name="interval_type">minutes</field>
     </record>
+    <record id="ir_cron_http_service_confirmation" model="ir.cron">
+        <field name="name">HTTP Service Monitoring : confirm KO services</field>
+        <field name="model_id" ref="maintenance_server_data.model_service_instance" />
+        <field name="state">code</field>
+        <field name="code">model.cron_confirm_http_ko_services()</field>
+        <field name="interval_number">2</field>
+        <field name="interval_type">minutes</field>
+    </record>
     <record id="ir_cron_maintenance_mode_expiry" model="ir.cron">
         <field
             name="name"