* pulls in datastore-leveldb update
* bump
* Applies LevelDb as metadata store. Adds option for repostore.
* Sets submodule to main branch
* I can do syntax, me
* Removes wildcard from metadata query key
* Applies leveldb instead of sqlite-in-memory for tests
* Restores query key wildcard.
* Pins nim-datastore to latest master
* bumps leveldb to 0.1.4
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Co-authored-by: Dmitriy Ryajov <dryajov@gmail.com>