ipv6 reconfiguration, require sudo privileges

[sorudev]

evernode config instance ipv6 could warn that root privileges are required or ask for sudo password like other evernode commands. Currently you can execute it as regular user and it fails:

`mkfifo: cannot create fifo '/usr/bin/sashimono/evernode-setup-helpers/helper_fifo': Permission denied
cat: /usr/bin/sashimono/evernode-setup-helpers/helper_fifo: No such file or directory
Error: EACCES: permission denied, open '/usr/bin/sashimono/evernode-setup-helpers/helper_fifo'
at Object.writeFileSync (node:fs:2352:20)
at app (/usr/bin/sashimono/evernode-setup-helpers/jshelper/index.js:52:393454)
at process.processTicksAndRejections (node:internal/process/task_queues:95:5) {
errno: -13,
code: 'EACCES',
syscall: 'open',
path: '/usr/bin/sashimono/evernode-setup-helpers/helper_fifo'

rm: cannot remove '/usr/bin/sashimono/evernode-setup-helpers/helper_fifo': No such file or directory
rm: cannot remove '/usr/bin/sashimono/evernode-setup-helpers/helper_fifo': No such file or directory
Invalid ipv6 subnet specified. It must be a valid ipv6 subnet in the CIDR format of "xxxx:xxxx:xxxx:xxxx::/NN".

}`

It also outputs wrong information that provided CIDR is invalid as above. With sudo it works ok.