feat: add custom icons for Zabbix, Centreon, Nagios, PRTG, Eaton, Riello, Vertiv
UPS: Eaton (lightning bolt, #E22000), Riello (battery+, #0066B3),
Vertiv (server rack, #0079A7)
Monitoring: Zabbix (activity line, #D40000), Centreon (bulb/hub, #0071CE),
Nagios (magnifier, #2D72D2), PRTG (speedometer, #7AB648)
All use thematic SVG paths on 24×24 viewBox, consistent with existing
custom icons (ICON_FREE, ICON_BASTION, ICON_MAIL, etc.).
READMEs (fr/en/es) updated.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
olivier
4c61ae9456