Add "onchain" mint functionality

[alpha-omega-labs]

Hello, Can you please add option for minty to work with entirely onchain NFT, where "Image" is stored in svg format onchain? With smart contract like: https://github.com/alpha-omega-labs/MoleculeNFT/blob/main/onchain.sol This would be very much needed for mint of molnft database collcetions and binary files on chain. Thank you!