Prepare UniversalCollection and BasicNFT Contracts and Docs

[joshuahannan]

Issue To Be Solved

UniversalCollection is a very useful contract and we should try to have it on testnet and mainnet as quickly as possible after the Crescendo upgrade. We also should have BasicNFT as an example with docs and a guide.

Suggest A Solution

• Revisit UniversalCollection and BasicNFT to make sure that the design is good and well-commented.
• Work with Flowty and FIND to see if their version of UniversalCollection can be used or if we want to promote a simpler one.

If we end up deciding to write our own:

• Write tests in flow-nft for these contracts to make sure they are working properly
• Make a deployment plan for testnet and mainnet
• Talk to community members who have contributed to the design to get their sign-offs and make sure to credit them for their role in designing the contracts.

Either way, we will need to:

• Update any relevant docs/tutorials to encourage developers to use UniversalCollection
• Write a blog post about UniversalCollection and BasicNFT