Manual finalization endpoint (#7059)

* Load block roots from fork choice where possible to avoid loading state from disk when serving block by range requests.

* Check if the start slot is newer than finalization (`start_slot >= finalized_slot`), and use fork choice in that case.

* force finalization endpoint

* cleanup

* Remove ds store

* Don't import blocks that conflict with the split

* Disconnect and ban peer if we get blocks conflicting manual checkpoint

* immediately commit state to cold db

* revert

* Fix descent from split check

* Add safety check to checkpoint when doing manual finalization.

---------

Co-authored-by: Jimmy Chen <jchen.tc@gmail.com>
Co-authored-by: Michael Sproul <michael@sigmaprime.io>
Co-authored-by: Pawan Dhananjay <pawandhananjay@gmail.com>

common/eth2/src/types.rs

@@ -1424,6 +1424,13 @@ pub struct StandardLivenessResponseData {
     pub is_live: bool,
 }
 
+#[derive(Debug, Serialize, Deserialize)]
+pub struct ManualFinalizationRequestData {
+    pub state_root: Hash256,
+    pub epoch: Epoch,
+    pub block_root: Hash256,
+}
+
 #[derive(Debug, Serialize, Deserialize)]
 pub struct LivenessRequestData {
     pub epoch: Epoch,