* Code cosmetics
* Re-org `aristo_merge`, internally split into sub-modules
why:
Became a burden for maintenance because it hosts two different
functionalities under the same merge paradigm: account/data merge
and snap proof merge where the latter produces a partial trie.
* Fix CoreDb tracer
* Ledger: fix potential account vs. storage tree sync problems
* Remove bound on the size of removable whole storage trees
* Activate `test_tracer_json`
392088e5e9