Extend container contract with node lists

[roman-khimov]

Is your feature request related to a problem? Please describe.

I'm always frustrated when we can't easily get a list of container nodes both for GETs of various kinds, but also for signature checks (refs. nspcc-dev/neofs-api#299).

Describe the solution you'd like

On epoch change IR can recalculate node lists and store them in container contract (netmap or a separate contracts are also possible, but container seems to be a bit more natural). If the list is the same --- nothing should be done. An event should be generated on the list change.

Describe alternatives you've considered

I doubt there are a lot of them if we want to check any container-wide signatures on-chain.