Shrink persisted fork choice data (#7805)

Closes:

- https://github.com/sigp/lighthouse/issues/7760


  - [x] Remove `balances_cache` from `PersistedForkChoiceStore` (~65 MB saving on mainnet)
- [x] Remove `justified_balances` from `PersistedForkChoiceStore` (~16 MB saving on mainnet)
- [x] Remove `balances` from `ProtoArray`/`SszContainer`.
- [x] Implement zstd compression for votes
- [x] Fix bug in justified state usage
- [x] Bump schema version to V28 and implement migration.

Cargo.lock

@@ -922,6 +922,7 @@ dependencies = [
  "tree_hash",
  "tree_hash_derive",
  "types",
+ "zstd 0.13.3",
 ]
 
 [[package]]
@@ -3567,6 +3568,7 @@ dependencies = [
  "proto_array",
  "state_processing",
  "store",
+ "superstruct",
  "tokio",
  "tracing",
  "types",