Issue title: Responsive breakpoints relative to a container
 Issue body: Sometimes we face situations where you need a responsive layout, but instead of using the viewport as the root for breakpoint calculations, we need it to be relative to the container.

E.g.: A QSplitter, each side with a grid of its own. As we resize the splitter columns, the contents of each respects the xs, sm, md, lg, xl breakpoints relative to the column container.

My suggestion is that we have a "QResponsiveContainer" that force every bbreakpoint related class nested into it to reacts to its dimensions instead of viewports.

Here are an example of this already working:
https://philipwalton.github.io/responsive-components/
 Comments: 
 Comment 0: Hi,

Use containerized QLayout. https://quasar.dev/layout/layout#Containerized-QLayout
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