Curio compatible Spade client

[alanshaw]

A Spade client that is compatible with Curio is required to enable Filecoin data onboarding to a broader range of Filecoin Storage Providers in the ecosystem.

Roughly, the Spade client needs to perform the following actions:

• Ask Spade API if any aggregates are available for it.
• Download pieces from aggregate recipie from roundabout.
• Assemble aggregate piece from downloaded segments.
• Obtain a signature for a deal proposal.
• Talk to Curio to get the deal done.

TODO: the above needs clarification/fleshing out.

More information on how Spade works can be found here:

• https://www.notion.so/storacha/Spade-Setup-on-Filecoin-Pipeline-Context-Dump-2ee5305b55248044b793cd738a79ef80
• https://www.notion.so/storacha/Spade-Filecoin-Questions-for-Riba-1585305b55248011abecc00069e52ceb