feat(transaction)!: allow multiple signers

[sdbondi]

Description

Allow multiple signers for a transaction

Motivation and Context

This enables many use cases including paying for another user's fees (gasless) and invoking two or more components owned by different public keys in the same transaction.

It is possible for a party to remove all signatures but one and still have a valid transaction. In future, we'll add a final signature that includes all signatures in the preimage.

How Has This Been Tested?

Manually. TODO: Multiple signer integration test

What process can a PR reviewer use to test or verify this change?

Submit transactions requiring badges from multiple public keys

Breaking Changes

• None
• Requires data directory to be deleted
• Other - Please specify

BREAKING CHANGE: wallet database changed, transaction struct changed

[github-actions]

Test Results (CI)

539 tests  +1   539 ✅ +1   1h 54m 29s ⏱️ - 26m 27s
 64 suites ±0     0 💤 ±0 
  2 files   ±0     0 ❌ ±0 

Results for commit b9c4f4e. ± Comparison against base commit 0ebb1fb.

This pull request removes 3 and adds 4 tests. Note that renamed tests count towards both.

tari_transaction ‑ transaction::export_bindings_substaterequirement
tari_transaction ‑ transaction::export_bindings_versionedsubstateid
tari_transaction ‑ transaction::tests::it_hashes_identically_to_a_substate_id

tari_dan_engine::account ‑ gasless
tari_transaction ‑ substate::export_bindings_substaterequirement
tari_transaction ‑ substate::export_bindings_versionedsubstateid
tari_transaction ‑ substate::tests::it_hashes_identically_to_a_substate_id

♻️ This comment has been updated with latest results.