* Rewrite remaining `AristoError` return code into `Result[void,AristoError]`
why:
Better code maintenance
* Update import sections
* Update Aristo DB paths
why:
More systematic so directory can be shared with other DB types
* More cosmetcs
* Update unit tests runners
why:
Proper handling of persistent and mem-only DB. The latter can be
consistently triggered by an empty DB path.
* Reorg of distributed backend access
details:
Now handled via API provided in `aristo_desc`.
* Rename `checkCache()` => `checkTop()`
why:
Better naming for top layer cache checker
also:
Provide cascaded fifos checker
* Provide `eq` directive for finding filter by exact filter ID (think block number)
* Some code beautification (for better code reading)
* State root reposition and reorg
details:
Repositioning is supported by forking a new descriptor. Reorg is then
accomplished by writing this forked state on the backend database.
* Rename FilterID => QueueID
why:
The current usage does not identify a particular filter but uses it as
storage tag to manage it on the database (to be organised in a set of
FIFOs or queues.)
* Split `aristo_filter` source into sub-files
why:
Make space for filter management API
* Store filter queue IDs in pairs on the backend
why:
Any pair will will describe a FIFO accessed by bottom/top IDs
* Reorg some source file names
why:
The "aristo_" prefix for make local/private files is tedious to
use, so removed.
* Implement filter slot scheduler
details:
Filters will be stored on the database on cascaded FIFOs. When a FIFO
queue is full, some filter items are bundled together and stored on the
next FIFO.
