Kintsugi review comments (#2831)

* Fix makefile

* Return on invalid finalized block

* Fix todo in gossip scoring

* Require --merge for --fee-recipient

* Bump eth2_serde_utils

* Change schema versions

* Swap hash/uint256 test_random impls

* Use default for ExecutionPayload::empty

* Check for DBs before removing

* Remove kintsugi docker image

* Fix CLI default value

beacon_node/src/cli.rs

@@ -406,9 +406,7 @@ pub fn cli_app<'a, 'b>() -> App<'a, 'b> {
                        collected from any blocks produced by this node. Defaults to a junk \
                        address whilst the merge is in development stages. THE DEFAULT VALUE \
                        WILL BE REMOVED BEFORE THE MERGE ENTERS PRODUCTION")
-                // TODO: remove this default value. It's just there to make life easy during merge
-                // testnets.
-                .default_value("0x0000000000000000000000000000000000000001"),
+                .requires("merge")
         )
 
         /*