Kura storage mechanism

[6r1d]

Matias Salimbene just asked about the persistence in Iroha 2.
My response is limited: the uncommitted transactions will be lost, but Kura should store other details.
I believe we should provide more details on the Kura mechanisms, but would like to hear your comments first.

Another topic we should cover someday is the behavior of a node that was turned off (in a kill -9 fashion or with machine reset) and restarted after.

[6r1d]

There's a snapshot storage mechanism that'll work on kill -9.
It may have updated some time before the process kill and will help process restoration.

[6r1d]

Config reference will have details on snapshots.