[WIP] p256 poc support

[aramikm]

Goal

The goal of this PR is

Closes

Discussion

Checklist

• [ ] Chain spec updated
• [ ] Custom RPC OR Runtime API added/changed? Updated js/api-augment.
• [ ] Design doc(s) updated
• [ ] Tests added
• [ ] Benchmarks added
• [ ] Weights updated

[aramikm]

Closing since these changes are already merged into passkey_poc branch