Sign up page breaks if PUBLIC_INSTANCE_URL starts with https://

**Describe the bug** If you set up an instance of Photon and set PUBLIC_INSTANCE_URL to something like https://lemmy.org , it works just fine until you click on "Sign up". Then, it sets the URL to https://localhost:3000/signup/https://lemmy.org which returns a 404. **To Reproduce** (if applicable) Steps to reproduce the behavior: - Run an instance of Lemmy in Docker, set PUBLIC_INSTANCE_URL=https://lemmy.org - Click on the "Sign up" link - Observe **Expected behavior** I think it should trim the https:// before sending you to the sign up page. **Versions** - Browser: Firefox - Photon version: 2.2.2