Refactor endpoint view to show more details

[jimeh]

To be able to show more details, I propose the following changes:

• Rename "Arguments" section to "Request Arguments"
• Add "Description" column to arguments table.
• Move "Potential Errors" section to end of the page.
• Add "Response Fields" section after "Request Arguments" and before "Returned Object" sections.
  • The "response Fields" section should be rendered like a table just like "Request Arguments" along with the "Description" column.
• Rename "Returned Object" section to "Response Object", "Response Structure", or "Response Example". I'm not 100% sure which might be the best fit.
• Support for deprecated fields and messages if/when Add support for marking fields as deprecated apia#5 gets addressed.

For reference, here is what the Get data center endpoint page looks like at the moment: