refactor(chain,wallet)!: move rusqlite things into it's own file

Also fix imports and rename `sqlite` module to `rusqlite_impl`.

example-crates/wallet_esplora_async/Cargo.toml

@@ -6,7 +6,7 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-bdk_wallet = { path = "../../crates/wallet", features = ["sqlite"] }
+bdk_wallet = { path = "../../crates/wallet", features = ["rusqlite"] }
 bdk_esplora = { path = "../../crates/esplora", features = ["async-https"] }
 tokio = { version = "1", features = ["rt", "rt-multi-thread", "macros"] }
 anyhow = "1"