* Split off `ReadOnlyStateDB` from `AccountStateDB` from `state_db.nim`
why:
Apart from testing, applications use `ReadOnlyStateDB` as an easy
way to access the accounts ledger. This is well supported by the
`Aristo` db, but writable mode is only parially supported.
The writable AccountStateDB` object for modifying accounts is not
used by production code.
So, for lecgacy and testing apps, the full support of the previous
`AccountStateDB` is now enabled by `import db/state_db/read_write`
and the `import db/state_db` provides read-only mode.
* Encapsulate `AccountStateDB` as `GenesisLedgerRef` or genesis creation
why:
`AccountStateDB` has poor support for `Aristo` and is not widely used
in favour of `AccountsLedger` (which will be abstracted as `ledger`.)
Currently, using other than the `AccountStateDB` ledgers within the
`GenesisLedgerRef` wrapper is experimental and test only. Eventually,
the wrapper should disappear so that the `Ledger` object (which
encapsulates `AccountsCache` and `AccountsLedger`) will prevail.
* For the `Ledger`, provide access to raw accounts `MPT`
why:
This gives to the `CoreDbMptRef` descriptor from the `CoreDb` (which is
the legacy version of CoreDxMptRef`.) For the new `ledger` API, the
accounts are based on the `CoreDxMAccRef` descriptor which uses a
particular sub-system for accounts while legacy applications use the
`CoreDbPhkRef` equivalent of the `SecureHexaryTrie`.
The only place where this feature will currently be used is the
`genesis.nim` source file.
* Fix `Aristo` bugs, missing boundary checks, typos, etc.
* Verify root vertex in `MPT` and account constructors
why:
Was missing so far, in particular the accounts constructor must
verify `VertexID(1)
* Fix include file
3e88589eb1