Show date of submission on dashboard

[dstansby]

On the dashboard (https://joss.theoj.org/dashboard), when looking at papers with no editor, it would be helpful to be able to sort by submission date, so editors can prioritise older submissions to pick up if they want to.

[warrickball]

I think the default sort is by submission date, newest first, but I agree it would be nice to (a) have explicit control over this and (b) be able to sort oldest first, which I don't think is possible.