Minor improvements in JS API

Improvements to some JS API features:

• Ecwid.openPage() JS API function can now open account subscription pages: Pages with parameters

• Ecwid.Cart.get() method now includes order ID Cart Object

• Hide extra fields from customers and store admin in Control Panel using new hidden value for the orderDetailsDisplaySection field: Show or hide extra fields in an order

Other changes:

• Added translations for name and description of returned shipping methods in Shipping API: Add shipping method

• New "Limits and Restrictions" section in Get store profile, which can be useful to integrations working with store catalog, e.g. dropshipping

• Minor bug fixes