Configure Static IP Addresses for Management Subinterfaces

To add static IP addresses to a specified subinterface, run the following command.
```
efa mgmt subinterface staticip add 
--subinterface <int-id> --ip1 <ip-addr/mask> --ip2 <ip-addr/mask>
```
To remove static IP addresses from a specified subinterface, run the following command.
```
efa mgmt subinterface staticip remove 
--subinterface <int-id>
```
To show all subinterfaces and the IP addresses that are attached to them, run the following command.
```
efa mgmt subinterface staticip show
```