Add config for altair-devnet-0

[parithosh]

Adds a config and genesis state for the altair-devnet-0.

MIN_GENESIS_ACTIVE_VALIDATOR_COUNT: 10000
# July 7, 2021, 12pm UTC
MIN_GENESIS_TIME: 1625659200
# Location for the altair star is 19h 50m 46.99855
GENESIS_FORK_VERSION: 0x19504699
# 86400 seconds (1 day)
GENESIS_DELAY: 86400

# Altair
ALTAIR_FORK_VERSION: 0x01000000
ALTAIR_FORK_EPOCH: 10

# Deposit contract
# ---------------------------------------------------------------
# Ethereum Goerli testnet
DEPOSIT_CHAIN_ID: 5
DEPOSIT_NETWORK_ID: 5
DEPOSIT_CONTRACT_ADDRESS: 0x3fe221a147E62eC697723fBfB4dd9505F4F966c7

total number of validators: 10,000

[michaelsproul]

Timeline looks good for us (Lighthouse)!

I've made a few requests for changes to the file formats to align with the defacto standard.

We may also need to update genesis.ssz if anyone sneaks a deposit in within the next 10 hours.

EDIT: nvm, I was thrown off by the MIN_GENESIS_TIME being today (July 7) rather than tomorrow. I think it will work fine.