Create "Change content author" built-in script for Space Admins

As a Confluence Space Admin

I would like the ability to change the author of pages 

So that the page author accurately reflects the user who owns the content

Acceptance Criteria

• The Space Admin should have the same experience (select by cql and choose author) as the Confluence admin's experience with that built-in script
• Standard Confluence permissions should be followed. Space Admins should only be able to choose content they have access to. 
• Track feature adoption