It has the service and requires unbound user created. Make it separate,
because some users of unbound-libs might not want or need anchor
maintenance. Make it also easier to add custom options to unbound-anchor
running from the service.
Do not start timer from unbound.service, start instead unbound-anchor
service before starting unbound. It would ensure root anchor is in the
place. Run it from single place from both timer and unbound service.
