Persist light client updates (#5545)

* persist light client updates

* update beacon chain to serve light client updates

* resolve todos

* cache best update

* extend cache parts

* is better light client update

* resolve merge conflict

* initial api changes

* add lc update db column

* fmt

* added tests

* add sim

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into persist-light-client-updates

* fix some weird issues with the simulator

* tests

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into persist-light-client-updates

* test changes

* merge conflict

* testing

* started work on ef tests and some code clean up

* update tests

* linting

* noop pre altair, were still failing on electra though

* allow for zeroed light client header

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into persist-light-client-updates

* merge unstable

* remove unwraps

* remove unwraps

* Update light_client_update.rs

* merge unstable

* move functionality to helper methods

* refactor is best update fn

* refactor is best update fn

* improve organization of light client server cache logic

* fork diget calc, and only spawn as many blcoks as we need for the lc update test

* fetch lc update from the cache if it exists

* fmt

* Fix beacon_chain tests

* Add debug code to update ranking_order ef test

* Fix compare code

* merge conflicts

* fix test

* Merge branch 'persist-light-client-updates' of https://github.com/eserilev/lighthouse into persist-light-client-updates

* Use blinded blocks for light client proofs

* fix ef test

* merge conflicts

* fix lc update check

* Lint

* resolve merge conflict

* Merge branch 'persist-light-client-updates' of https://github.com/eserilev/lighthouse into persist-light-client-updates

* revert basic sim

* small fix

* revert sim

* Review PR

* resolve merge conflicts

* Merge branch 'unstable' into persist-light-client-updates

testing/ef_tests/tests/tests.rs

@@ -900,6 +900,11 @@ fn merkle_proof_validity() {
     MerkleProofValidityHandler::<MainnetEthSpec>::default().run();
 }
 
+#[test]
+fn light_client_update() {
+    LightClientUpdateHandler::<MinimalEthSpec>::default().run();
+}
+
 #[test]
 #[cfg(feature = "fake_crypto")]
 fn kzg_inclusion_merkle_proof_validity() {