GraphQL 296 set billing address

[VitaliyBoyko]

This PR covers setting billing address on the cart.

Fixed Issues (if relevant)

1. [Cart Operations] Set Billing Address #296: [Cart Operations] Set Billing Address

Example query:

mutation {
 setBillingAddressOnCart(
   input: {
     cart_id: "maskedQuoteId"
     billing_address: {
       address: {
         firstname: "test firstname"
         lastname: "test lastname"
         company: "test company"
         street: ["test street 1", "test street 2"]
         city: "test city"
         region: "test region"
         postcode: "887766"
         country_code: "US"
         telephone: "88776655"
         save_in_address_book: false
       }
       use_for_shipping: true
     }
   }
 )
}

PS: PR based on my previous work (implementing multi-shipping).
In order to see changes properly, I've done PR to the multi-shipping branch.
I gonna change the base branch since multi-shipping be merged.

[magento-cicd2]

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