Clippy clean (#536)

* Change into_iter to iter

* Fix clippy 'easy' warnings

* Clippy eth2/utils

* Add struct NetworkInfo

* Clippy for types, utils, and beacon_node/store/src/iters.rs

* Cargo fmt

* Change foo to my_foo

* Remove complex signature

* suppress clippy warning for unit_value in benches

* Use enumerate instead of iterating over range

* Allow trivially_copy_pass_by_ref in serde_utils

beacon_node/rest_api/src/response_builder.rs

@@ -27,7 +27,7 @@ impl ResponseBuilder {
                     e
                 ))
             })
-            .map(|h| String::from(h))?;
+            .map(String::from)?;
 
         // JSON is our default encoding, unless something else is requested.
         let encoding = match content_header {
@@ -85,7 +85,7 @@ impl ResponseBuilder {
         Response::builder()
             .status(StatusCode::OK)
             .header("content-type", content_type)
-            .body(Body::from(body))
+            .body(body)
             .map_err(|e| ApiError::ServerError(format!("Failed to build response: {:?}", e)))
     }