Async-ify NFT ownership verification and image retrieval

[NoahSaso]

Right now, NFT ownership is validated and the image is fetched on every profile query. This is redundant and slow.

Let's move both of those processes elsewhere, out of the profile query itself.

One solution is to move NFT ownership and NFT image fetching to our Snapper instance, which will cache the requests and handle updating them on the specified interval automatically.

Alternatively, to avoid external dependencies, we can build a system right into pfpk:

• store image on NFT update
• create route that verifies NFT ownership and removes it from the profile if no longer owned by the wallet
• asynchronously fire that request whenever a profile is queried, optimistically returning the NFT but updating it in the background for next time