Ship List UI Improvement: Lock nav & column headers to top of window

[sjmagy]

Hello, I’m opening several requests for UI improvements as individual issues since I suspect some may be easier to do than others and would be cleaner to track 1 issue per ticket. (I’d help if I had any current coding skills.)

Make the top nav bar and column headers stay visible at the top of the window when scrolling down the list of ships; there are so many numbers displayed that it's easy to get lost in which column of data you're looking at. Alternately, allow for column selection / highlight.