Fix the units report when there are many units

[lmoureaux]

Split the window horizontally instead of vertically, which facilitates scrolling.

Closes #2313.

[blabber]

Works as intended, but the layout is a little inconsistent now:

I have hacked this together on view_units.ui:

What do you think?

[lmoureaux]

I agree that your proposed layout looks better. Does it look ok when no units are waiting?

[blabber]

The "units waiting" group is hidden in this case. Feel free to test my proposal (which is a good idea anyways): blabber/freeciv21@38f5dea

[jwrober]

@hugomflavio and I worked together to evaluate this PR as well. There are a few things we need to think about on this before its ready if we keep the change horizontally opposed:

1. The new UI group should have a spacer in it that is the same as the button bar so the two tables are horizontally aligned
2. The vertical spacer should be a slider so the player can expand/contract each side as needed - this is super important on smaller displays
3. The units waiting table should by default push over the empty space on the units table and leave very little slack

All that said, I personally would prefer that units waiting is vertically opposed to units like I did it initially. It works best on smaller displays, which we have many players in this category. Setting some limiters so the units table can't take up the whole screen and bury the units waiting table when there are many units in both tables is important. My thinking is when units waiting is present we change the geometry of the units table so it is max half screen "tall" with a horizontal slider in the middle. Then we see the units waiting table at the bottom half, the default slider in the middle is at mid-screen and should allow the player to slide up/down to see more/less of each table on the screen as needed.

[jwrober]

see note above

[jwrober]

Another alternative idea is to change the view to a tabbed interface with units table on one tab and units waiting on a second. Then each table can use the whole screen.

[lmoureaux]

A resizeable split screen can be done with a QSplitter. Closing this PR as the required changes go in a vastly different direction.