1. Add the ability to set `include_ifmib_iface_prefix` for SNMP.
```
.IP "include_ifmib_iface_prefix PREFIX1 PREFIX2 ..."
Sets the interface name prefixes to include in the IF-MIB data collection.
For servers with a large number of interfaces (ppp, dummy, bridge, etc)
the IF-MIB processing will take a large chunk of CPU for ioctl calls
(on Linux). A set of space separated interface name prefixes will
reduce the CPU load for IF-MIB processing. For example, configuring
"include_ifmib_iface_prefix eth dummy lo" will include only interfaces
with these prefixes and ignore all others for IF-MIB processing.
```
https://github.com/net-snmp/net-snmp/blob/0175f031c1bd902bf9fbd5c698298f645f449606/man/snmpd.conf.5.def#L105C1-L112C65
Proposed CLI
```
set service snmp interface-mib-prefix eth
set service snmp interface-mib-prefix dummy
```
Or
```
set service snmp interface-mib prefix eth
set service snmp interface-mib prefix dummy
```
2. Another useful option `ifmib_max_num_ifaces NUM`
```
.IP "ifmib_max_num_ifaces NUM"
Sets the maximum number of interfaces included in IF-MIB data collection.
For servers with a large number of interfaces (ppp, dummy, bridge, etc)
the IF-MIB processing will take a large chunk of CPU for ioctl calls
(on Linux). Setting a reasonable maximum for the CPU used will
reduce the CPU load for IF-MIB processing. For example, configuring
"ifmib_max_num_ifaces 500" will include only the first 500 interfaces
based on ifindex and ignore all others for IF-MIB processing.
```
Proposed CLI:
```
set service snmp interface-mib max xx
```