Optimizations, disable val client sync check & additional lcli tools (#834)

* Start adding interop genesis state to lcli

* Use more efficient method to generate genesis state

* Remove duplicate int_to_bytes32

* Add lcli command to change state genesis time

* Add option to allow VC to start with unsynced BN

* Set VC to do parallel key loading

* Don't default to dummy eth1 backend

* Add endpoint to dump operation pool

* Add metrics for op pool

* Remove state clone for slot notifier

* Add mem size approximation for tree hash cache

* Avoid cloning tree hash when getting head

* Fix failing API tests

* Address Michael's comments

* Add HashMap::from_par_iter

validator_client/src/cli.rs

@@ -14,6 +14,12 @@ pub fn cli_app<'a, 'b>() -> App<'a, 'b> {
                 .default_value(&DEFAULT_HTTP_SERVER)
                 .takes_value(true),
         )
+        .arg(
+            Arg::with_name("allow-unsynced")
+                .long("allow-unsynced")
+                .help("If present, the validator client will still poll for duties if the beacon
+                      node is not synced.")
+        )
         /*
          * The "testnet" sub-command.
          *