1.57.0 lints (#2850)

## Issue Addressed

New rust lints

## Proposed Changes

- Boxing some enum variants
- removing some unused fields (is the validator lockfile unused? seemed so to me)

## Additional Info

- some error fields were marked as dead code but are logged out in areas
- left some dead fields in our ef test code because I assume they are useful for debugging?

Co-authored-by: realbigsean <seananderson33@gmail.com>

testing/ef_tests/src/cases/genesis_validity.rs

@@ -7,7 +7,8 @@ use types::{BeaconState, EthSpec, ForkName};
 
 #[derive(Debug, Clone, Deserialize)]
 pub struct Metadata {
-    description: String,
+    #[serde(rename(deserialize = "description"))]
+    _description: String,
 }
 
 #[derive(Debug, Clone, Deserialize)]