[UI] Improve application flags by visibly grouping related flag options



Currently, application flags are shown as a single 3x3 block of options (with one segment being empty). In order to easier see which of these flags are related (and sometimes exclusive), I suggest to visually group them:

Grouping is currently done on a row basis, but especially when selected flags form a column, this gets very confusing.

Example: https://stamp.community/apps/1

Grouping can be as simple as using stronger lines between rows, but I think spacing would look better.