Add option to hide LHS sidebar stats #585

I don't really use them, and they take valuable vertical space which becomes annoying when you're in many teams and have to scroll the list of team buttons. It's worse when you're connected to both GitLab and GitHub, since now you easily lose almost 25% of your vertical space to these plugins.

Of course I could use a selector in my ad blocker to hide it, but a setting for it would be much cleaner!