[ci] Support lock transfers in the Scan registry

Implements canton-network/splice-sv-fa-locking#112.

• Ingest GovernanceLockTransfer proposals into the Scan store.
• Add ScanStore.listGovernanceLocksByKey, which lists the locks with a given key, largest amount first, using the governance lock type and subject index.
• Serve the TSv1 accept context of a GovernanceLockTransfer: it discloses up to 20 locks matching the proposal's source key, which is as many as the accept merges, and their LockedAmulets. The reject and withdraw contexts need no lock disclosures.

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Cluster Testing

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