Add eip_3076 crate

[macladson]

Issue Addressed

#7894

Proposed Changes

Moves the Interchange format from slashing_protection and thus removes the dependency on slashing_protection from eth2 which can now just depend on the slimmer eip_3076 crate.

[macladson]

These types imports add a lot of bloat to this crate. It doesn't really matter much right now since eth2 needs types anyway but it might be worth considering some kind of core or primitives feature in types which only imports these basic types, especially if this crate gets used in contexts where the rest of the types aren't already required.

[michaelsproul]

Perfect, I love this!

[mergify]

This pull request has been removed from the queue for the following reason: pull request dequeued.

Pull request #8206 has been dequeued. The pull request rule doesn't match anymore. The following conditions don't match anymore:

• label=ready-for-merge.

You can check the last failing draft PR here: #8211.

You should look at the reason for the failure and decide if the pull request needs to be fixed or if you want to requeue it.
If you do update this pull request, it will automatically be requeued once the queue conditions match again.
If you think this was a flaky issue instead, you can requeue the pull request, without updating it, by posting a @mergifyio requeue comment.

[michaelsproul]

@macladson weirdly one of the interchange tests is failing with an out-of-bounds error, can you take a look? 🙏

https://github.com/sigp/lighthouse/actions/runs/18548309242/job/52870463882?pr=8211

[macladson]

Whoops, I de-duplicated the Interchange construction right before I pushed and broke it 😅
Fixed now

[macladson]

Hmm still getting failures 1/3 times.. Something about that test is non-deterministic

[macladson]

It was from HashMap ordering. I've just gone ahead and removed those extra checks since minification behaviour is more thouroughly checked here anyway -> https://github.com/sigp/lighthouse/blob/unstable/validator_client/slashing_protection/src/interchange_test.rs#L247-L302