Rust 1.54.0 lints (#2483)

## Issue Addressed

N/A

## Proposed Changes

- Removing a bunch of unnecessary references
- Updated `Error::VariantError` to `Error::Variant`
- There were additional enum variant lints that I ignored, because I thought our variant names were fine
- removed `MonitoredValidator`'s `pubkey` field, because I couldn't find it used anywhere. It looks like we just use the string version of the pubkey (the `id` field) if there is no index

## Additional Info



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

common/logging/src/lib.rs

@@ -140,9 +140,7 @@ impl<'a> slog_term::RecordDecorator for AlignedRecordDecorator<'a> {
             write!(
                 self,
                 "{}",
-                std::iter::repeat(' ')
-                    .take(self.message_width - self.message_count)
-                    .collect::<String>()
+                " ".repeat(self.message_width - self.message_count)
             )?;
             self.message_active = false;
             self.message_count = 0;