* Change into_iter to iter
* Fix clippy 'easy' warnings
* Clippy eth2/utils
* Add struct NetworkInfo
* Clippy for types, utils, and beacon_node/store/src/iters.rs
* Cargo fmt
* Change foo to my_foo
* Remove complex signature
* suppress clippy warning for unit_value in benches
* Use enumerate instead of iterating over range
* Allow trivially_copy_pass_by_ref in serde_utils
- Replaced most instances of PublicKey with KeyPair, since they need to be passed into each validator thread now.
- Pulled out a bunch of FreeAttestations, and replaced with regular Attestations (as per Paul's suggestion)
- Started generalising pubkeys to 'signers' (though they are still just Keypairs)
- Added validator_index into a few structs where relevant
- Removed the SlotClock and DutiesReader from the BlockProducer and Attester services, since this logic is now abstracted to the higher level process.
- Added a Hash trait to the Keypair (rather than just pubkey) which assumes the Pubkey uniquely defines it.