Add error handling to all api routes

[gemcoder21]

We can extend endpoint like get_name_resolve, to return a custom error struct

#[get("/name/resolve/<name>?<chain>")]
pub async fn get_name_resolve(
    name: &str,
    chain: &str,
    name_client: &State<Mutex<NameClient>>,
) -> Result<Json<NameRecord>, NotFound<String>> {
...
}