As a developer, I want a simple interface for creating & querying date-based indexes by range

The base implementation would create a configurable sharded `Path` structure based on some input timestamp for a paired entry (perhaps provided as a two-element tuple i.e. `(DateTime, EntryData)`).

Temporal sharding granularity could be defined by an established crate or some other enum for year / month / day / hour / min / sec, where the interval determines how "deep" to shard the path based on components of the input date. Smaller intervals would probably include all parent intervals as `Path.parent()`s up the tree, to allow browsing the contribution graph in a temporally ordered manner.

This gives us a resultant period-based API, where we can ask eg. "show me all the entries of this type **created yesterday**". Note the "yesterday" afforded by a "day" sharding granularity, other configurations would make other query sizes possible.