Smol PP: positions with AI-generated profile picture

[werg]

• [x] Create a new lending contract ("MetaLending" -- fork of StableLending2) which includes the ability to attach metada (import ERC721Metadata from OpenZeppelin)
• [x] Set it up with a url pointing somewhere (for now it can just be to the id or something)
• [x] The above probably makes the contract too big and we will need to cut some more functionality (probably some view functions that we don't actually use)
• [x] Integrate this new lending contract into the UI
• [x] Create all the other contracts (like what we had to do when switching from StableLending -> StableLending2)
• [x] Copy code from DSG frontend for generating images using stable diffusion, but modifying it to only generate images AFTER the new position has been minted on the chain
• [x] Do some prototype for showing image in the UI
• [x] probably add a special migration contract for people to convert teir positions to one with a picture attached
• [ ] Before deploying, fix the bug where contracts can't be position owners

[BrunoEleodoro]

Ref: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC721/extensions/IERC721Metadata.sol