multisig nfts and versioning

[ryanleecode]

When a multisig is created, nothing is actually broadcasted onchain to denote that it is created. if you are added to a multisig, you don't know that actually a part of it. In #661 we serialize the multisig setup as a hash. It would be interesting if we can also serialize the "capi multisig version" as part of the hash for upgradability purposes and then upload this hash to IPFS, and mint an NFT to each of the multisig owners with the hash as part of the NFT metadata.