Electra attestation interfaces (#13937)

* config values

* block protos

* get_committee_indices

* proto and ssz

* attestation interface

* Revert "Auxiliary commit to revert individual files from deadb2183723511721b3288c7168808a4fa97c64"

This reverts commit 32ad5009537bc5ec0e6caf9f52143d380d00be85.

* todos

* get_attesting_indices

* Revert "Auxiliary commit to revert individual files from dd2789723f90b15eb1f874b561d88d11dcc9c0bf"

This reverts commit f39644ed3cb6f3964fc6c86fdf4bd5de2a9668c8.

* beacon spec changes

* Fix pending attestation. Build ok

* Electra: add electra version

* Electra: consensus types

* gocognit exclusion

* @potuz's suggestion

* build fix

* interfaces for indexed att and slashing

* indexed att usage

* BuildSignedBeaconBlockFromExecutionPayload

* slashing usage

* grpc stubs

* remove unused methods

* Electra attestation interfaces

* cleanup

* tests

* make linter happy

* simple casting

* test fixes

* Fix spectest failures

* Regen pb and ssz files

* Handle "not ok" type assertion cases

* Setters that check version should always return an error. SetAttesterSlashings and SetAttestations

* gofmt

* Fix TestMinSpanChunksSlice_CheckSlashable

---------

Co-authored-by: terence tsao <terence@prysmaticlabs.com>
Co-authored-by: Preston Van Loon <preston@pvl.dev>

runtime/version/fork.go

@@ -8,6 +8,7 @@ const (
 	Bellatrix
 	Capella
 	Deneb
+	Electra
 )
 
 var versionToString = map[int]string{
@@ -16,6 +17,7 @@ var versionToString = map[int]string{
 	Bellatrix: "bellatrix",
 	Capella:   "capella",
 	Deneb:     "deneb",
+	Electra:   "electra",
 }
 
 // stringToVersion and allVersions are populated in init()