(This PR is a split from https://github.com/thoughtbot/administrate/pull/1494, which was mixing two different concerns.)
When the user presses tab, the browser is expected to move to the next link. Since all cells in the table are links, the user has to press tab many times (once per column) in order to move to the next row:
Since each row works as a link, so much tabbing should not be necessary. This change makes it so that each row is tabbable, but not the cells.
There are two exceptions: action links, and data that should actually be represented as a link (eg: instances of Field::Url or Field::Email). These are not affected by this change, and are still accessible with an additional tab press for each cell. The row will be highlighted first, then each data link:
