Move "add view display..." button to the top

[tkuhn]

Move this button on the user pages to the top of the page; it doesn't make sense anymore at the bottom.

[ashleycaselli]

The button is now handled as a separate component called AddViewDisplayButton.

[tkuhn]

I looked into it but it's unclear how it should integrate with the other row-sections. Just a single section with only the button looks strange when it's at the top. And it probably should be after the intro section (description, users, etc.) for the Spaces. This needs some more thought, or possibly another approach altogether. Leaving it as we have it right now for the moment...