Enabling SSL everywhere, hooray!
After several hours of fighting with nginx and SELinux (the first rule to productivity on CentOS is to always first check that SELinux is not causing the problem), I finally got Let’s Encrypt working on all my websites. All the way from GitLab to my blog and so forth.
I don’t know if it’s good practice to redirect HTTP to HTTPS though, but for now, that’s what I’m doing.