Fix new clippy lints (#2036)

## Issue Addressed

NA

## Proposed Changes

Fixes new clippy lints in the whole project (mainly [manual_strip](https://rust-lang.github.io/rust-clippy/master/index.html#manual_strip) and [unnecessary_lazy_evaluations](https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_lazy_evaluations)). Furthermore, removes `to_string()` calls on literals when used with the `?`-operator.

testing/eth1_test_rig/src/ganache.rs

@@ -35,7 +35,7 @@ impl GanacheInstance {
     ) -> Result<Self, String> {
         let stdout = child
             .stdout
-            .ok_or_else(|| "Unable to get stdout for ganache child process")?;
+            .ok_or("Unable to get stdout for ganache child process")?;
 
         let start = Instant::now();
         let mut reader = BufReader::new(stdout);