Add a command to submit contracts to the Flow NFT Catalog

[psiemens]

Freshmint users will need to add their deployed contracts to the Flow NFT Catalog: https://www.flow-nft-catalog.com/

There should be an easy way for users to:

• Submit their contract using the fresh CLI (e.g. fresh submit-to-catalog --network testnet)
  • On testnet, it'd be great if the contract could be automatically added
  • On mainnet, this should return a URL to the proposal page
• Submit their contract using the Node.js library (e.g. contract.submitToCatalog())

cc @bshahid331 @aishairzay @prpatel05