Slider or progress bar for artifact research

[rdw-software]

This feature was partially (and experimentally, I might add) added to some old beta version, but ultimately removed as I didn't think it would be worth the time after they changed the maximum research time to 3 hours for everyone.

It may be worth revisiting should 7.3 bring back longer research time, as it would be relatively simple to add it to the new GUI, but for the time being I'll consider this a fairly unimportant feature.