* Multiple storage batches at a time
why:
Previously only some small portion was processed at a time so the peer
might have gone when the process was resumed at a later time
* Renamed some field of snap/1 protocol response object
why:
Documented as `slots` is in reality a per-account list of slot lists. So
the new name `slotLists` better reflects the nature of the beast.
* Some minor healing re-arrangements for storage slot tries
why;
Resolving all complete inherited slots tries first in sync mode keeps
the worker queues smaller which improves logging.
* Prettify logging, comments update etc.