Create UI helper classes to address white space issues

[nicdford]

Is your feature request related to a problem? Please describe.
UI's that have fixed width elements leave awkward white spaces at various screen widths.
@JoryHogeveen phil said you did most the css for this dfv grid view, is there a reason we have to use fixed widths? I was concerned maybe the draggability functionality requires a fixed width?

Describe the solution you'd like
We could develop some UI helper classes (using flexbox or maybe the new css grid specs) to address the need for more flexible user interfaces in the ever-demanding responsive world.

[JoryHogeveen]

The fixed items where already there, I just "relocated" them for that tiles view.
At that time I thought the same thing.. "Why fixed" but didn't change it because I thought there were other UI items what could rely on that CSS.

[quasel]

let's do it :)