Update chainspec p2p and etc

[0xmrree]

Issue Addressed

Missing values in /eth/v1/config/spec #8571
- there will be follow up PR for the re org props

Proposed Changes

1. As per above issue from EF dev ops, I added

"EPOCHS_PER_SUBNET_SUBSCRIPTION": "256",
  "ATTESTATION_SUBNET_COUNT": "64",
  "ATTESTATION_SUBNET_EXTRA_BITS": "0",
  "UPDATE_TIMEOUT": "8192",
  "DOMAIN_BLS_TO_EXECUTION_CHANGE": "0x0a000000"

to /eth/v1/config/spec
2. Had to change the minimal config for UPDATE_TIMEOUT to get currents tests to pass. This is ok given UPDATE_TIMEOUT is not used in lighthouse as this config for light client spec from altair
3. ATTESTATION_SUBNET_PREFIX_BITS is now dynamically calculated and shimmed into the /eth/v1/config/spec output as advised by @michaelsproul

Testing

1. ran cargo nextest run -p types and passed all tests, see below

...
        PASS [   0.006s] types withdrawal::withdrawal_request::tests::test_ssz_round_trip
        PASS [   0.007s] types withdrawal::withdrawal_request::tests::test_tree_hash_root
        PASS [   0.010s] types::committee_cache default_values
        PASS [   5.431s] types::committee_cache initializes_with_the_right_epoch
        PASS [   5.489s] types::committee_cache fails_without_validators
        PASS [   5.534s] types::state cache_initialization
        PASS [   5.617s] types::state beacon_proposer_index
        PASS [   0.238s] types::state decode_base_and_altair
        PASS [   5.740s] types::committee_cache min_randao_epoch_correct
        PASS [   6.236s] types::committee_cache shuffles_for_the_right_epoch
        PASS [  19.782s] types::state committees::current_epoch_committee_consistency
        PASS [  19.816s] types::state committees::next_epoch_committee_consistency
        PASS [  19.540s] types::state committees::previous_epoch_committee_consistency
────────────
     Summary [  25.263s] 265 tests run: 265 passed, 0 skipped

2. Started beacon node via ./target/release/lighthouse bn --network sepolia ... and ran

curl http://localhost:5052/eth/v1/config/spec | jq '.data | {
  EPOCHS_PER_SUBNET_SUBSCRIPTION,
  ATTESTATION_SUBNET_COUNT,
  ATTESTATION_SUBNET_EXTRA_BITS,
  ATTESTATION_SUBNET_PREFIX_BITS,
  UPDATE_TIMEOUT,
  DOMAIN_BLS_TO_EXECUTION_CHANGE
}'

which returned

{
  "EPOCHS_PER_SUBNET_SUBSCRIPTION": "256",
  "ATTESTATION_SUBNET_COUNT": "64",
  "ATTESTATION_SUBNET_EXTRA_BITS": "0",
  "ATTESTATION_SUBNET_PREFIX_BITS": "6",
  "UPDATE_TIMEOUT": "8192",
  "DOMAIN_BLS_TO_EXECUTION_CHANGE": "0x0a000000"
}

[michaelsproul]

You'll need to rebase on unstable to get CI to pass

[michaelsproul]

I'll be OOO until Jan 12 but someone might be able to review