Shared Persistence

[luisschwab]

With bdk#1582 merged, floresta-chain can share persistence with bdk-chain.

[luisschwab]

bitcoindevkit/bdk#2038

[luisschwab]

The ideia is to implement bdk_chain's ChainOracle trait for Floresta's FlatChainStore. This way, the wallet doesn't need to keep a LocalChain, which would be redundant. The Wallet can simply rely on the Node's own chain implementation for canonicalization and source of truth.

[oleonardolima]

Concept ACK