While doing CLI changes for SNMP configuration, few changes are made in backend to handle the modified CLI.
** Changes**
- "community" for "snmp trap" is also made as "configurable". snmpd_conf.j2 is modified to handle the same.
- Changed the snmp.yml file generation from postStartAction to preStartAction in docker_image_ctl.j2 specific to SNMP docker, to ensure that the snmp.yml is generated before sonic-cfggen generates the snmpd.conf.
- Changed to make the code common for management vrf and default vrf. Users can configure snmp trap and snmp listening IP for both management vrf and default vrf.