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/store/src/metrics.rs

@@ -94,7 +94,7 @@ pub fn scrape_for_metrics(db_path: &PathBuf) {
     let db_size = if let Ok(iter) = fs::read_dir(db_path) {
         iter.filter_map(std::result::Result::ok)
             .map(size_of_dir_entry)
-            .fold(0_u64, |sum, val| sum + val)
+            .sum()
     } else {
         0
     };