feat(bridge-signer): implement FROST threshold signer node

[noot]

Summary

implement FROST threshold signer node which implements the FrostParticipantService gRPC service defined in #1948. the bridge withdrawer can then collect signature partials from various threshold signer nodes to sign a withdrawal transaction in a more distributed manner.

Background

improves security of the withdrawer over having one private key used; instead, we can employ an m-of-n threshold signature scheme to sign withdrawals.

Changes

• implement FROST threshold signer node which implements the FrostParticipantService gRPC service
• currently, the signer is evm-rollup specific; when it receives a sequencer withdrawal tx to sign, it verifies that the withdrawals are valid using an evm rollup node. specifically, it performs the same logic that the withdrawer uses to create the withdrawal tx in the first place (one tx = every withdrawal in an evm block converted to an action) to verify.

Testing

tested with the withdrawer in #1948; see https://www.notion.so/astria-org/bridge-threshold-withdrawer-testing-1936bd31a90c803ab33ccc1221f545a1?pvs=4

Changelogs

Ensure all relevant changelog files are updated as necessary. See
keepachangelog for change
categories. Replace this text with e.g. "Changelogs updated." or "No updates
required." to acknowledge changelogs have been considered.

Related Issues

closes #1937