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
--- `count`: specifies that the value of at least minimum and at most maximum objects encountered in
+++ `count`: specifies that the value of *at least* `minimum` and *at most* `maximum` objects encountered in