Avoid accessing config, pubkey2index, index2pubkey from cached state

[twoeths]

Problem description

as part of #8650 once we switch to using native state transition, we don't have a CachedBeaconStateAltair or CachedBeaconStateAllForks anymore so we should not access config, pubkey2index, index2pubkey from it

Solution description

we need to implement a global cache and use it instead, something like:

export type GlobalCache {
  config: BeaconConfig;
  pubkey2index: PubkeyIndexMap;
  index2pubkey: Index2PubkeyCache;
}

Additional context

No response

[twoeths]

one way to make sure it works is to have config as a private property of EpochCache class