Token Claims EIP712 signature verification (and ethereum primitives switch)

[MOZGIII]

This PR adds eip712-token-claim, refactors the eip712 code to enable more reuse, and switches the codebase to ethereum primitives crate.

It also resolves the incorrect use of "EVM address" wording. The terms we have are EVM account and Ethereum address. Using the term "EVM address" is discouraged as confusing.

See #430.

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eip712-token-claim

To do

• implementation
• test that recovery returns the expected eth address with a valid signature
• test that recovery doesn't return the expected eth address with an invalid signature

[dmitrylavrenov]

Looks good. Left some comments!

[MOZGIII]

I decided we'd want to change the trait at token claims to only do the signer recovering instead of full verification, and move the verification out of the trait. It makes a lot of sense to do it like that, as the verification is not something one should be able to override. But we'll address it alter, I'll create an issue for this, and we can merge this PR.