It is more semantic to use a `<button>` tag in the place of an `<a>`
when there is no other page being linked to. In this circumstance, we're
using JavaScript to present a modal to the user on click.
This change makes the "Upload" and "Rename" buttons appear in the
browser's tab index.
There was a display issue, where navbar items's outline styles were
being cut off due to the parent `<nav>` element's margin and padding.
Fortunately, we can do away with the navbar wrapper div entirely. It was
not doing anything important except defining its children as
`TableObject` items. But we can just do this on the `<nav>` itself.
If the user has edit permissions, the "History" button is shown in a
button group with "Edit" and "Rename". If the user does not have edit
permissions, it's shown by itself.
This commit also renames the label from "Page History" to "History".
* If navbar is too wide, use overflow-x: scroll
* Add initial mobile nav menu
* Use CSS classes instead of IDs for jQuery events
* Change content x-axis padding for mobile devices
* Recompile assets for mobile menu feature