Create NFT based reserve for krievo collective's receiving dUSD funding

[monsieurbulb]

Enable function within krievo/virto to enable collectives to propose funding in return for pledging / assignng NFTs representing their concepts to a shared reserve.

Assets are minted on Kusama AH and escrowed using the payment pallet.

Linked to initiatives - NFTs are locked until work / project is completed/delivered.

Collectives can unlock NFTs and trade them once delivery is complete.

Collectives must keep NFTs locked to access more dUSD funding.