* Expose IntoDisk and FromDisk in zebra-state
* Implement database serialization for SaplingScanningKey Strings
* Implement serialization for Vec<SaplingScannedResult> (Vec<transaction::Hash>)
* Implement seralization for SaplingScannedDatabaseIndex
* Add an is_empty() method
* Add a read method for a specific index, and document it
* Implement writing scanner results to the database
* Make read name more explicit
* Implement writing scanner keys
* Implement reading sapling keys
* Spawn blocking tasks correctly in async code
* Change storage results methods to use the database
* Update tests that use storage
* Use spawn_blocking() for database methods
* Change the check interval to slightly less than the block interval
* Expose raw database methods with shielded-scan
* fix `scan_task_starts` test
* minor doc change in test
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Co-authored-by: Alfredo Garcia <oxarbitrage@gmail.com>
teor