780 build structured url api

[abotteram]

Summary

This PR can be summarized in the following changelog entry:

• Adds buildStructuredUrl function.

Relevant technical choices:

• This is the first step towards fixing Yoast/wordpress-seo#3514. It introduces a function that later on will be used to built the permalink in the snippet editor.

Test instructions

This PR can be tested by following these steps:

• Link yoast-components with this PR to wordpress-seo and build the project.
• In your browsers console go to any admin page where window.yoast.components is loaded, like the Dashboard.
• In the console, you can test the function, for example like this:

  window.yoast.components.utils.buildStructuredUrl( "http://www.example.com/%category%/%postname%", {
  category: [ "transportation", "flying" ],
  postname: "the-cost-of-flying",
  } );

Fixes #780

[Edit by Andrea] Changed "http://www.example.com/%category%/%postname%, { to "http://www.example.com/%category%/%postname%", {

[IreneStr]

CR2 done 👍

[afercia]

Acceptance 👍

Agreed to add some more documentation for each step.