[Naming] Add subheading: A CryptoKitties Sample App

[alxflw]

In preparation for the GTM launch, we decided to add a subheading to the name. So, the full naming becomes:

Kitty Items: CryptoKitties Sample App

To incorporate the changes in the repository, the list below captures what needs to be updated. Content will be provided by David.

Github Repo

• [x] Update repo description ("about"): Kitty Items: CryptoKitties Sample App

README

• [x] Update logo image to include subheading: Crypto Kitties Sample App
• [x] Update intro to use new name: Kitty Items: CryptoKitties Sample App is a complete NFT marketplace [...]

package.json

• [x] Update description: A CryptoKitties Sample App, learn how to create an NFT Marketplace

app.json

• [x] Update description: A CryptoKitties Sample App, learn how to create an NFT Marketplace

Header.jsx

• [x] Add subtitle: Crypto Kitties Sample App

constants.js

• [x] Update title: A CryptoKitties Sample App, learn how to create an NFT Marketplace

AppContainer.jsx

• [x] Update metadata:

  <meta name="description" content="Get motivated to develop for Web3 and build an NFT marketplace!"/>