NMS-6746: Improve readability SnmpMonitor

- Table for Operation mode reformatted in source
- Description table shortened
- Operator description added force line breaks
- Changed snmp-config.xml format as file
- Reformatted examples and the used OIDs
- Renamed the example service from All_Static_Routes to All-Static-Routes to look less like source code
---The SnmpMonitor is *configrued* to test if the fan status returns _ok(2)_ and the the service is marked as _up_.
+++The SnmpMonitor is configured to test if the fan status returns _ok(2)_. If so, the service is marked as _up_.