Add the public debian ntp pool to the sesi_rocquencourt subnet
Add the public debian ntp pool to the sesi_rocquencourt subnet

Some hosts on this subnet are routed via the old SESI network, some via
the new network, so the set of NTP servers accessible is disjunct. NTP
is resilient enough that we can just merge both server lists without a
problem.

SoftwareHeritage/puppet-swh-site,SoftwareHeritage/puppet-swh-site,SoftwareHeritage/puppet-swh-site,SoftwareHeritage/puppet-swh-site,SoftwareHeritage/puppet-swh-site