Update public documentation on "How to connect your store"

[pmusolino]

Update the public documentation related to "how to connect your store", since it's outdated and it doesn't include how to connect the store with application passwords. -> https://woo.com/document/woocommerce-ios/#connect-to-your-store

[dangermattic]

🚫 Please add a type label (e.g. type: enhancement) and a feature label (e.g. feature: stats) to this issue.