Be able to put the banner above the main content but not above the sidebar

[awesomerobot (Kris)]

I’ve just opened a PR that will add a plugin outlet setting so it can be displayed like this:

@tshenry can you try it out and merge it when you have a chance? DEV: plugin outlet setting for sidebar, prettier by awesomerobot · Pull Request #15 · discourse/discourse-versatile-banner · GitHub