Metadata already defined and can be re-used in cw721

[taitruong]

This struct:

launchpad/packages/sg-metadata/src/lib.rs

Lines 16 to 45 in 5c94381

	pub struct Metadata {
	/// This is the URL to the image of the item. Can be just about any type of image (including
	/// SVGs, which will be cached into PNGs by OpenSea), and can be
	/// [IPFS](https://github.com/ipfs/is-ipfs) URLs or paths. We recommend using a 350 x 350 image.
	pub image: Option<String>,
	/// Raw SVG image data, if you want to generate images on the fly (not recommended). Only use
	/// this if you're not including the `image` parameter.
	pub image_data: Option<String>,
	/// This is the URL that will appear below the asset's image on OpenSea and will allow users to
	/// leave OpenSea and view the item on your site.
	pub external_url: Option<String>,
	/// A human readable description of the item. Markdown is supported.
	pub description: Option<String>,
	/// Name of the item.
	pub name: Option<String>,
	/// These are the attributes for the item, which will show up on the OpenSea page for the item.
	pub attributes: Option<Vec<Trait>>,
	/// Background color of the item on OpenSea. Must be a six-character hexadecimal without a
	/// pre-pended #.
	pub background_color: Option<String>,
	/// A URL to a multi-media attachment for the item. The file extensions GLTF, GLB, WEBM, MP4,
	/// M4V, OGV, and OGG are supported, along with the audio-only extensions MP3, WAV, and OGA.
	///
	/// Animation_url also supports HTML pages, allowing you to build rich experiences and
	/// interactive NFTs using JavaScript canvas, WebGL, and more. Scripts and relative paths within
	/// the HTML page are now supported. However, access to browser extensions is not supported.
	pub animation_url: Option<String>,
	/// A URL to a YouTube video.
	pub youtube_url: Option<String>,
	}

Could be removed and instead expose from cw721. Like:

• v18 Metadata is defined here: https://github.com/public-awesome/cw-nfts/blob/release/v0.18.0/contracts/cw721-metadata-onchain/src/lib.rs#L19-L29
• v19 Metadata:
  • NftExtensionMsg for msg handling: https://github.com/public-awesome/cw-nfts/blob/release/v0.19.0/packages/cw721/src/msg.rs#L954-L968
  • NftExtension for state handling: https://github.com/public-awesome/cw-nfts/blob/release/v0.19.0/packages/cw721/src/state.rs#L259-L269