Update EIP-7002: convert to system contract

[lightclient]

First stab at converting 7002 to a system contract. A few notable changes:

• Instead of directly reading storage to compute the exits in the block, this has be combined in the system call to the contract. The exits are returned as normal return data. They should be packed in 68 byte chunks.
• The contract now allows for callers to read the current excess_exits count by calling the contract with no calldata.
• The contract does not return an over payment of the fee. Instead, callers should use the aforementioned getter to compute the exact fee before calling the contract.

The bytecode is created from the following repo: https://github.com/lightclient/7002asm

[eth-bot]

✅ All reviewers have approved.

[mkalinin]

Suggested change

	calldataloa
	calldataload

[mkalinin]

EXCESS_RETURN_GAS_STIPEND should be removed as well as no longer used

[lightclient]

@mkalinin updated based on your review, PTAL.

[github-actions]

The commit 4284de0 (as a parent of 3408475) contains errors.
Please inspect the Run Summary for details.

[eth-bot]

All Reviewers Have Approved; Performing Automatic Merge...

[mkalinin]

Awesome work!!

[loga4]

Based on the recent changes to the EIP-7002, 2 questions here:

1. The ability to return unspent gas to the sender has been removed, but the Utilizing CALL block remains https://eips.ethereum.org/EIPS/eip-7002#utilizing-call-to-return-excess-payment. Is this option supposed to appear in the future or did you forget to remove it from the document?

2. Is it correct - there is no restriction on incoming queue, meaning I can send a exit request of 100/1000 validators for the same price?

(there are no open PRs about 7002, so I tried to find an relevant place to ask these questions)

@lightclient

[lightclient]

You can in general direct questions to https://ethereum-magicians.org/t/eip-7002-execution-layer-triggerable-exits/14195

1. This is an omission, thank you for letting us know. It shall be removed.
2. The fee grows exponentially but it updates each block. You can send as many exits as you like for the fee of a certain block. However, the dequeue process only reads a fixed number per block.