* CoreDb: Merged all sub-descriptors into `base_desc` module
* Dissolve `aristo_db/common_desc.nim`
* No need to export `Aristo` methods in `CoreDb`
* Resolve/tighten methods in `aristo_db` sub-moduled
why:
So they can be straihgt implemented into the `base` module
* Moved/re-implemented `KVT` methods into `base` module
* Moved/re-implemented `MPT` methods into `base` module
* Moved/re-implemented account methods into `base` module
* Moved/re-implemented `CTX` methods into `base` module
* Moved/re-implemented `handler_{aristo,kvt}` into `aristo_db` module
* Moved/re-implemented `TX` methods into `base` module
* Moved/re-implemented base methods into `base` module
* Replaced `toAristoSavedStateBlockNumber()` by proper base method
why:
Was the last for keeping reason for keeping low level backend access
methods
* Remove dedicated low level access to `Aristo` backend
why:
Not needed anymore, for debugging the descriptors can be accessed
directly
also:
some clean up stuff
* Re-factor `CoreDb` descriptor layout and adjust base methods
* Moved/re-implemented iterators into `base_iterator*` modules
* Update docu