Selectively showing headers in the editor tab?

[execveat]

We can't do it right now as the built-in editor that InQL won't work properly. But if we move to another editor (e.g. in order to support syntax highlighting and tab completion), it might be a good idea to selectively show some of the headers. E.g. cookies and authorization. Or maybe show all headers besides the general ones (host, content-type, etc).