Kill sidebar animation and change main container width instead of translating it

[cjcenizal]

Currently hovering over the sidebar triggers a translation animation of the main container, which moves it to the right. This reveals the text for the links in the sidebar, and causes the right-most content in the main container to be clipped by the right side of the window.

Per discussion with @uboness and @alt74 , let's remove this animation and make the change immediate. Also, instead of translating the main container, let's change its width instead. This will cause a redraw of its content, but will prevent the content from being clipped.

Related to #7467 and #7665 (allow pinning of sidebar).

[epixa]

The redraw of content is way worse than the content being clipped. It will, for example, result in all visualizations on the page rebuilding, which is both expensive and disruptive. Crack open 4.x, create a dashboard with a ton of visualizations, and then change your browser window size by a pixel or two, and you'll get the idea.

If the navbar has an explicit toggle so it will stay expanded, then it makes sense to resize, but for any mouseover animation, we shouldn't be resizing anything.

[Bargs]

I agree with @epixa, a full page redraw is really jarring and will be painfully slow on complex screens.

[kimjoar]

Very much agree on clipping being the best choice. Having to redraw can cause a whole lot of issues depending on the content. I don't see any problem with the content temporarily being off-screen — it's not the focus either way, the focus is the navigation.

[cjcenizal]

Addressed by #7723