Remove post-altair initialize_beacon_state_from_eth1 from specs

[KatyaRyazantseva]

This PR removes post-altair initialize_beacon_state_from_eth1 from specs.

Issue addressed #3663

[KatyaRyazantseva]

@hwwhww electra and eip-7594 ci tests fail, because add_validator_to_registry(state, pubkey, withdrawal_credentials, Gwei(0)) in apply_deposit() leaves state.balances empty. This change has been marked as Modified in Electra:EIP7251. It causes some assertion failures like assert spec.is_valid_genesis_state(state) and others. I found the same failures in the dev branch when running citest. Example:

def initialize_beacon_state_from_eth1(eth1_block_hash: Hash32,
                                      eth1_timestamp: uint64,
                                      deposits: Sequence[Deposit]) -> BeaconState:
    fork = Fork(
    ....
        for index, validator in enumerate(state.validators):
            # balances are empty
            balance = state.balances[index] 
            # validator's effective balance is empty, validator is not active
            validator.effective_balance = min(balance - balance % EFFECTIVE_BALANCE_INCREMENT, 
                  MAX_EFFECTIVE_BALANCE) 
            if validator.effective_balance == MAX_EFFECTIVE_BALANCE:
                validator.activation_eligibility_epoch = GENESIS_EPOCH
                validator.activation_epoch = GENESIS_EPOCH

[dapplion]

@KatyaRyazantseva there appears to be an involuntary commit of .idea files

[hwwhww]

@KatyaRyazantseva

Suggestions:

1. remove tests/core/pyspec/eth2spec/test/bellatrix/genesis/test_initialization.py file since it is no longer relevant
2. for the test cases in tests/core/pyspec/eth2spec/test/phase0/genesis/test_initialization.py, replace @with_all_phases with @with_phases([PHASE0]) so that we only test initialize_beacon_state_from_eth1 helper with Phase0.

[hwwhww]

LGTM! 👍

No more redundant initialize_beacon_state_from_eth1 when writing a new feature!

[jtraglia]

LGTM 👍