portconfig option to configure Tx power and laser frequency of ZR tra…

[prgeor]

Cherry-pick of PR #2197

Added new configuration CLI options to configure Tx power and laser frequency of ZR transceiver module

Previous command output (if the output of a command-line utility has changed)

New command output (if the output of a command-line utility has changed)

root@sonic:~# portconfig -p Ethernet0 -P -28.3
Setting target Tx output power to -28.3 dBm on port Ethernet0
root@sonic:~# redis-cli -n 4 hgetall "PORT|Ethernet0" 
 1) "admin_status"
 2) "up"
 3) "alias"
 4) "Ethernet1/1"
 5) "index"
 6) "1"
 7) "lanes"
 8) "1,2,3,4,5,6,7,8"
 9) "laser_freq"
10) "1000"
11) "speed"
12) "400000"
13) "tx_power"
14) "-28.3"
root@sonic:~# 


root@sonic:~# portconfig -p Ethernet0 -F 191000
Setting laser frequency to 191000 GHz on port Ethernet0
root@sonic:~# redis-cli -n 4 hgetall "PORT|Ethernet0" 
 1) "admin_status"
 2) "up"
 3) "alias"
 4) "Ethernet1/1"
 5) "index"
 6) "1"
 7) "lanes"
 8) "1,2,3,4,5,6,7,8"
 9) "laser_freq"
10) "191000"
11) "speed"
12) "400000"
13) "tx_power"
14) "-28.3"
root@sonic:~# 

[prgeor]

@yxieca @qiluo-msft could you approve and merge. This is a cherry-pick PR