Prop 447: Upload CW721 Base Contract

Passing this proposal will upload the CW721 NFT base contract to the Osmosis chain.

## Details
This proposal would upload the current version (v0.16.0) of the base CW721 NFT contract, enabling the minting of non-fungible tokens on Osmosis in compliance with the CW721 specification.

The base CW721 contract allows the minting of NFTs and contains the three components of the specification.

* Base - Handles ownership, transfers and allowances of the tokens
* Metadata extension - Allows the token to contain unique metadata
* Enumerable extension - Allows the contract to publish the full list of tokens minted and make them discoverable.

Full Documentation: https://github.com/CosmWasm/cw-nfts/tree/main/contracts/cw721-base

## Release Version
https://github.com/CosmWasm/cw-nfts/releases/tag/v0.16.0

## Version of Compiler used
cosmwasm/workspace-optimizer:0.12.9

## Checksum
d5fa68c6dcf210fd14e556a21d2f7a4976933da33caa97348ad99e0ec4373d9f

Commonwealth Thread: https://commonwealth.im/osmosis/discussion/10117-cw721-contract-upload-proposal