Make nx graph sidebar width-adjustable

[astanb]

My library and app names can be quite long, so they are getting truncated in the sidebar, making it a really bad experience to know which specific entry I am dealing with, it has to be trial and error. See attached screenshot:

This can be resolved by changing the width of the container using CSS in the dev tools inspector, but it would be nice to be able to either drag the container using the mouse or set a wider default css value.