Storing large blobs in a "WITHOUT ROWID" table turns out to be extremely
slow when the tree must be rebalanced.
* Split out keystore capability into separate interface, making each
keystore a separate instance
* Disable "WITHOUT ROWID" optimization by default
* Implement prefix lookup that allows iterating over all values with a
certain prefix in their key
* Add build_dcli target and add it to CI
* Fix local imports for dcli
* And use local imports for all other files too
* Use local imports in tests and rlpx protocols
* port kvstore from nim-beacon-chain
* remove old database backends
* use kvstore in trie database
* add sqlite dep
* avoid template param double evaluation
* clean up heterogenous lookup todo
Ștefan Talpalaru
Jacek Sieka
Kim De Mey