Infinite Scrolling for Marketplace

[ricklove]

This enables infinite scrolling by not loading the nft metadata or dom until it is visible.

• The tokenSale data is obtained from the contract storage for all marketplace tokens (with 9 initial items).
• Upon scrolling to the bottom, it loads another chunk of items (8 items right now).
• This effectively reduces the need for lazy loading of images since nothing is loaded until it is needed.
• The VisibilityTrigger component is a reusable component that can be used anywhere a trigger like this is needed.

Note: a much cleaner and more generic approach was attempted that used a simple dataSource, but unfortunately redux only allows serializable data.

[ricklove]

Making a few improvements to this.

[ricklove]

Done with improvements

[ricklove]

Added one more improvement to handle loading errors for individual tokens.

[ricklove]

This is not working for me after the merge (piñata), not sure if it is just me.

[ricklove]

This should be ready to merge