feat(db): Refactor storage libraries (#371)

crates/storage/db/src/lib.rs

@@ -0,0 +1,26 @@
+//! Rust database abstraction and concrete database implementations.
+
+#![warn(missing_docs, unreachable_pub)]
+#![deny(unused_must_use, rust_2018_idioms)]
+#![doc(test(
+    no_crate_inject,
+    attr(deny(warnings, rust_2018_idioms), allow(dead_code, unused_variables))
+))]
+
+/// Abstracted part of database, containing traits for transactions and cursors.
+pub mod abstraction;
+
+mod implementation;
+pub mod tables;
+mod utils;
+
+#[cfg(feature = "mdbx")]
+/// Bindings for [MDBX](https://libmdbx.dqdkfa.ru/).
+pub mod mdbx {
+    pub use crate::implementation::mdbx::*;
+    pub use reth_libmdbx::*;
+}
+
+pub use abstraction::*;
+pub use reth_interfaces::db::Error;
+pub use tables::*;