## Proposed Changes
Lots of lint updates related to `flat_map`, `unwrap_or_else` and string patterns. I did a little more creative refactoring in the op pool, but otherwise followed Clippy's suggestions.
## Additional Info
We need this PR to unblock CI.
## Issue Addressed
NA
## Proposed Changes
This PR adds some more fancy macro magic to make it easier to add a new built-in (aka "baked-in") testnet config to the `lighthouse` binary.
Previously, a user needed to modify several files and repeat themselves several times. Now, they only need to add a single definition in the `eth2_config` crate. No repetition 🎉
## Issue Addressed
NA
## Proposed Changes
Copied from #2083, changes the config milliseconds_per_slot to seconds_per_slot to avoid errors when slot duration is not a multiple of a second. To avoid deserializing old serialized data (with milliseconds instead of seconds) the Serialize and Deserialize derive got removed from the Spec struct (isn't currently used anyway).
This PR replaces #2083 for the purpose of fixing a merge conflict without requiring the input of @blacktemplar.
## Additional Info
NA
Co-authored-by: blacktemplar <blacktemplar@a1.net>
## Issue Addressed
- Resolves#1706
## Proposed Changes
Updates dependencies across the workspace. Any crate that was not able to be brought to the latest version is listed in #1712.
## Additional Info
NA
