Sensors

[bmridul]

- What I did
EntityMIB and SensorMIB support for board voltage and current sensors.
Ref Hld : sonic-net/SONiC#1394

- How I did it
Modified implementations of entity MIB and SensorMIB to fetch data from sensor data from redis.
- How to verify it

Unit test Added.
Verified with SNMP walk on target.

root@sonic:/home/cisco# docker exec -it snmp snmpwalk -v2c -c public 127.0.0.1 iso.3.6.1.2.1.47.1.1.1.1 | grep 200240150
iso.3.6.1.2.1.47.1.1.1.1.2.200240150 = STRING: "MB_VP54P0V"
iso.3.6.1.2.1.47.1.1.1.1.3.200240150 = ""
iso.3.6.1.2.1.47.1.1.1.1.4.200240150 = INTEGER: 200000000
iso.3.6.1.2.1.47.1.1.1.1.5.200240150 = INTEGER: 8
iso.3.6.1.2.1.47.1.1.1.1.6.200240150 = INTEGER: 1
iso.3.6.1.2.1.47.1.1.1.1.7.200240150 = STRING: "MB_VP54P0V"
iso.3.6.1.2.1.47.1.1.1.1.8.200240150 = ""
iso.3.6.1.2.1.47.1.1.1.1.9.200240150 = ""
iso.3.6.1.2.1.47.1.1.1.1.10.200240150 = ""
iso.3.6.1.2.1.47.1.1.1.1.11.200240150 = ""
iso.3.6.1.2.1.47.1.1.1.1.12.200240150 = ""
iso.3.6.1.2.1.47.1.1.1.1.13.200240150 = ""
iso.3.6.1.2.1.47.1.1.1.1.14.200240150 = ""
iso.3.6.1.2.1.47.1.1.1.1.15.200240150 = ""
iso.3.6.1.2.1.47.1.1.1.1.16.200240150 = INTEGER: 2

root@sonic:/home/cisco# docker exec -it snmp snmpwalk -v2c -c public 127.0.0.1 iso.3.6.1.2.1.99.1.1.1 | grep 200240150
iso.3.6.1.2.1.99.1.1.1.1.200240150 = INTEGER: 4
iso.3.6.1.2.1.99.1.1.1.2.200240150 = INTEGER: 8
iso.3.6.1.2.1.99.1.1.1.3.200240150 = INTEGER: 0
iso.3.6.1.2.1.99.1.1.1.4.200240150 = INTEGER: 54050
iso.3.6.1.2.1.99.1.1.1.5.200240150 = INTEGER: 1

- Description for the changelog

[liat-grozovik]

@Junchao-Mellanox could you please help to review that PR?

[liat-grozovik]

@bmridul please update your code PR to be on the latest so once code is approved we can move forward and merge