refactor: structure of an hexagonal architecture

Created a kernel crate to store models and future action implementations.
Will be useful to create admin cli.

lib/kernel/src/repositories/users.rs

@@ -0,0 +1,14 @@
+// user repositories
+
+use crate::models::user::User;
+
+use super::storage::Storage;
+use anyhow::{Result, Context};
+
+async fn get_user_by_id(storage: &Storage, user_id: &str) -> Result<User> {
+    sqlx::query_as::<_, User>("SELECT * FROM users WHERE id = $1")
+        .bind(user_id)
+        .fetch_one(&storage.0)
+        .await
+        .context("To get user from claim")
+}