[6.x] Adjust Field editor for improved large screen readability.

[martyf]

Many fields in the Field editor have 50% column widths, which works well.

But on a larger screen (I work on a 27" monitor, and currently my browser window is around 1800px wide which gives me plenty of breathing space in the CP), the white space introduced makes it harder to read, and fields take up an unnecessarily large amount of space.

My eye has to hunt across each row, with select fields that are mostly empty space because values are so small. It makes this part of the new UI feel more overwhelming.

Here's a mockup, where on a larger screen, those 50% columns could go to 33% columns for larger screens:

This decreases the amount of empty space, and to me increases the readability, and my ability to scan more quickly.

This 33% idea works well down to ~1200-1300px wide - then going to 50% makes total sense before it falls to single columns at around 1000 (which could be a fraction too early - there's still lots of space at that level).

I know each interface is different and fields have different requirements so there is no one-size-fits-all but would be so great for columns to adjust at an additional breakpoint (i.e. single, 50, 33) to allow for a better layout for large screen sizes.