fix: require authentication for free urls

.env.sample

@@ -34,6 +34,7 @@ COMPOSE_FILE="compose.yml"
 # CMD_ALLOW_ANONYMOUS_EDITS=false
 # CMD_ALLOW_EMAIL_REGISTER=true
 # CMD_ALLOW_FREEURL=false
+# CMD_REQUIRE_FREEURL_AUTHENTICATION=true
 # CMD_ALLOW_GRAVATAR=true
 # CMD_ALLOW_ORIGIN=localhost
 # CMD_COOKIE_POLICY=lax