Rework form pages into the new DSC3 CSS

[miggol]

This is kind of huge, but I do imagine that whoever bites this off will most likely get good at it after one or two pages. After which things should go smoothly.

Basically, we want every page to use a layout like Page 1 in major/4, with a stepper to the side, help texts in the other sidebar, and bootstrap form controls.