[sudoers]: add ipintutil in sudoer file (sonic-net#6857)

This PR is port of sonic-net#6845 for 201911

show ip interfaces is enhanced recently to support multi ASIC platforms in this sonic-net/sonic-utilities#1437. The ipintutil script as to run as sudo user, to get the ip interface from each namespace.
Add this script to the sudoer file so that show ip interface command is available for user with read-only permissions

Signed-off-by: Arvindsrinivasan Lakshmi Narasimhan <arlakshm@microsoft.com>

files/image_config/sudoers/sudoers

@@ -27,6 +27,7 @@ Cmnd_Alias      READ_ONLY_CMDS = /sbin/brctl show, \
                                  /usr/bin/docker exec * ps aux, \
                                  /usr/bin/docker ps*, \
                                  /usr/bin/generate_dump, \
+                                 /usr/bin/ipintutil, \
                                  /usr/bin/lldpctl, \
                                  /usr/bin/lldpshow, \
                                  /usr/bin/psuutil *, \