Demo Store For First Time Devs

[dandlezzz]

Currently, it is not possible to create a marketplace from the marketplaces repo. Let's change that. This would be great for development and production as well. Marketplace creation shouldn't be dependent on holaplex.dev|com or the holaplex/holaplex repo.

[kespinola]

Instead of hacking in a create form into marketplaces which shouldn't naturally be able to spawn themeselves we should put together a demo storefront and set that as the default when you boot up the marketplace.