Add EF launchpad import (#1381)

## Issue Addressed

NA

## Proposed Changes

Adds an integration for keys generated via https://github.com/ethereum/eth2.0-deposit (In reality keys are *actually* generated here: https://github.com/ethereum/eth2.0-deposit-cli).

## Additional Info

NA

## TODO

- [x] Docs
- [x] Tests

Co-authored-by: Michael Sproul <michael@sigmaprime.io>

validator_client/src/lib.rs

@@ -7,12 +7,12 @@ mod fork_service;
 mod initialized_validators;
 mod is_synced;
 mod notifier;
-mod validator_definitions;
 mod validator_store;
 
 pub use cli::cli_app;
 pub use config::Config;
 
+use account_utils::validator_definitions::ValidatorDefinitions;
 use attestation_service::{AttestationService, AttestationServiceBuilder};
 use block_service::{BlockService, BlockServiceBuilder};
 use clap::ArgMatches;
@@ -29,7 +29,6 @@ use slot_clock::SystemTimeSlotClock;
 use std::time::{SystemTime, UNIX_EPOCH};
 use tokio::time::{delay_for, Duration};
 use types::EthSpec;
-use validator_definitions::ValidatorDefinitions;
 use validator_store::ValidatorStore;
 
 /// The interval between attempts to contact the beacon node during startup.