feat: validate stacks fees

[AshtonStephens]

Description

Closes #1439

This PR is from another PR (#1392) that got split up to separate Bitcoin and Stacks behavior.

Changes

• Adds a configuration parameter to the signer that prevents the signer from signing Stacks transactions that exceed that fee.
• Adds tests that ensure the configuration and fee enforcement work.

Testing Information

unit and integration tests

Checklist:

• I have performed a self-review of my code
• My changes generate no new warnings
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[AshtonStephens]

Only adding Mateo and Daniel because you two were the active reviewers of #1392

[AshtonStephens]

Existing comments on this code can be found in the original PR of which this is half:

• Add configurable max stx fee and avoid signing Bitcoin transactions with absurd fees #1392

[cylewitruk]

This LGTM, but I'll let @djordon or @matteojug approve since I didn't spend much time on the previous PR.

[djordon]

Largely looks good. We need to get those child tickets sorted out. Also, we need to figure out when to update the immunefi branch.

[djordon]

We should combine this test with the one below to something like this

#[test_case("dkg_max_duration" ; "dkg_max_duration")]
#[test_case("bitcoin_presign_request_max_duration" ; "bitcoin_presign_request_max_duration")]
#[test_case("signer_round_max_duration" ; "signer_round_max_duration")]
#[test_case("stacks_fees_max_ustx" ; "stacks_fees_max_ustx")]
fn zero_values_for_nonzero_fields_fail_in_signer_config(field: &str) {
    clear_env();

    std::env::set_var(format!("SIGNER_SIGNER__{}", field.to_uppercase()), "0");

    Settings::new_from_default_config()
        .expect_err("value for must be non zero");
}

You'll probably need to add use test_case::test_case near the top of the tests module.

[djordon]

Shouldn't this stay commented, since we don't want to give the impression that signers should set it unless they need to?

[matteojug]

I'm not even sure we want this block here, we usually don't add the ones with a default we may want to "silently" change in this file (not even commented out)

[djordon]

Yeah, let's remove it.

[AshtonStephens]

Removed everywhere.

[djordon]

Well we want it in the default.toml, just not in the mainnet or devenv ones.

[djordon]

Actually, you can keep it in the devenv one too, just not the mainnet one.

[djordon]

We should mention that this value must be greater than zero.

[matteojug]

I'm not even sure we want this block here, we usually don't add the ones with a default we may want to "silently" change in this file (not even commented out)