Vertical Navigation with Categories

I’d like to add vertical navigation on the left-hand side of my Discourse site which lists all the categories. And I’d like this to be displayed on every page of the site like this:

I’ve seen the Custom Layouts Plugin which looks awesome! But I’m hosting my site on Communiteq (formerly DiscourseHosting) and can’t install any plugins without upgrading to a pro plan.

Which means I’d be paying an additional $120/year just for a sidebar category list.

If that’s the only way to do, then I’ll have to do that. But is there a simpler way to get a simple navigation like this using a theme component instead of a plugin?