Add ML-DSA-87

[fpseverino]

Add ML-DSA-87

Checklist

• I've run tests to see all new and existing tests pass
• I've followed the code style of the rest of the project
• I've read the Contribution Guidelines
• I've updated the documentation if necessary

If you've made changes to gyb files

• I've run .script/generate_boilerplate_files_with_gyb and included updated generated files in a commit of this pull request

Motivation:

See #355

Modifications:

Add the "87" parameter set in MLDSA_boring.swift.gyb, add tests for MLDSA87 and update the test vectors for both ML-DSA 65 and 87

Result:

MLDSA87 is now available

[Lukasa]

Very nice @fpseverino, thanks!