Bump the MSRV to 1.62 and using #[derive(Default)] on enums (#3304)

## Issue Addressed

N/A

## Proposed Changes

Since Rust 1.62, we can use `#[derive(Default)]` on enums. ✨ 

https://blog.rust-lang.org/2022/06/30/Rust-1.62.0.html#default-enum-variants

There are no changes to functionality in this PR, just replaced the `Default` trait implementation with `#[derive(Default)]`.

Dockerfile

@@ -1,4 +1,4 @@
-FROM rust:1.58.1-bullseye AS builder
+FROM rust:1.62.0-bullseye AS builder
 RUN apt-get update && apt-get -y upgrade && apt-get install -y cmake libclang-dev
 COPY . lighthouse
 ARG FEATURES