Provide methods to handle SELFDESTRUCT

[Scooletz]

The SELFDESTRUCT code requires an ability to destroy any account with its underlying storage tree in one call like:

IWorldState.Destroy(anAccountToBeDestroyed)

This should be implemented in a way that is aligned with the write-trough behavior of Paprika's tree in PageDb so that the information if flushed down not necessarily immediately which could result in a lot of writes. If a page contains only storage information for the given account, it could be easily batch.RegisterForFutureReuse() so maybe it's possible to do a deep walk through the tree from the given level and find all the matches and write just the top page.

[Scooletz]

This could be done in a marker fashion, that either sets a special key (then it requires querying) or writes a special account value.

[Scooletz]

Or just check and iterate. For accounts with small storages, it will be several deletes. With accounts with Massive Storage Trees, it can be just removal of the MST + special operation for the Merkle.