* Re-model persistent database access
why:
Storage slots healing just run on the wrong sub-trie (i.e. the wrong
key mapping). So get/put and bulk functions now use the definitions
in `snapdb_desc` (earlier there were some shortcuts for `get()`.)
* Fixes: missing return code, typo, redundant imports etc.
* Remove obsolete debugging directives from `worker_desc` module
* Correct failing unit tests for storage slots trie inspection
why:
Some pathological cases for the extended tests do not produce any
hexary trie data. This is rightly detected by the trie inspection
and the result checks needed to adjusted.
* For snap sync, publish `EthWireRef` in sync descriptor
why:
currently used for noise control
* Detect and reuse existing storage slots
* Provide healing module for storage slots
* Update statistic ticker (adding range factor for unprocessed storage)
* Complete mere function for work item ranges
why:
Merging interval into existing partial item was missing
* Show av storage queue lengths in ticker
detail;
Previous attempt shows average completeness which did not tell much
* Correct the meaning of the storage counter (per pivot)
detail:
Is the # accounts that have a storage saved