New settings row to install WC Shipping plugin

[JorgeMucientes]

For M1 of the Onboarding Shipping Labels project we'll display a new section inside settings to trigger the installment of WC Shipping plugin:

This new section will only be displayed under similar conditions we check to display the banner in order detail screen:

• WCShip is not installed or not enabled.
• The store is located in US.
• The currency is USD.