Edit Page form updates and table of contents

Updated the "Edit Page" form to use the new accordion layout instead of horizontal tabs. This brings a number of (hopefully) improvements:

• Instead of showing the content areas in horizontal tabs, they now show in the table of contents in the sidebar.
• All blocks and content layout fields now show in the sidebar. You can click on one to jump to it.
• You can search the sidebar - useful if you're trying to find a specific block on a long page.
• On apps like the Blog app, this will now include any fields, not just blocks.

The goals with this update include:

• Having a unified view for adding and editing content.
• Making it easier to search for content. Previously, content could be hidden by a tab. 
• Prevent having to scroll back to the top just to go to another tab.
• Make it easier to find content to edit.

Please contact us with any feedback that you may have.