#### Why I did it
SNMP query over IPv6 does not work due to issue in net-snmp where IPv6 query does not work on multi-nic environment.
To get around this, if snmpd listens on specific ipv4 or ipv6 address, then the issue is not seen.
We plan to configure Management IP and Loopback IP configured in minigraph.xml as SNMP_AGENT_ADDRESS in config_db., based on changes discussed in https://github.com/sonic-net/SONiC/pull/1457.
##### Work item tracking
- Microsoft ADO **(number only)**:26091228
#### How I did it
Modify minigraph parser to update SNMP_AGENT_ADDRESS_CONFIG with management and Loopback0 IP addresses.
Modify snmpd.conf.j2 to use SNMP_AGENT_ADDRESS_CONFIG table if it is present in config_db, if not listen on any IP.
Main change:
1. if minigraph.xml is used to configure the device, then snmpd will listen on mgmt and loopback IP addresses,
2. if config_db is used to configure the device, snmpd will listen IP present in SNMP_AGENT_ADDRESS_CONFIG if that table is present, if table is not present snmpd will listen on any IP.
#### How to verify it
config_db.json created from minigraph.xml for single asic VS image with mgmt and Loopback IP addresses.
```
"SNMP_AGENT_ADDRESS_CONFIG": {
"10.1.0.32|161|": {},
"10.250.0.101|161|": {},
"FC00:1::32|161|": {},
"fec0::ffff:afa:1|161|": {}
},
.....
snmpd listening on the above IP addresses:
admin@vlab-01:~$ sudo netstat -tulnp | grep 161
tcp 0 0 127.0.0.1:3161 0.0.0.0:* LISTEN 71522/snmpd
udp 0 0 10.250.0.101:161 0.0.0.0:* 71522/snmpd
udp 0 0 10.1.0.32:161 0.0.0.0:* 71522/snmpd
udp6 0 0 fec0::ffff:afa:1:161 :::* 71522/snmpd
udp6 0 0 fc00:1::32:161 :::* 71522/snmpd
```
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