♻️ refactor: Move similar javascript inline code out of line

- Move variables oid, oid_likes out of line
- Move background-blur out of line
- Move fetch-repo code out of line

assets/js/background-blur.js

@@ -0,0 +1,13 @@
+function backgroundBlur() {
+  const script = document.currentScript;
+  const targetId = script && script.getAttribute("data-target-id") ? script.getAttribute("data-target-id")
+    : (console.error("data-target-id is null"), null);
+
+  window.addEventListener("scroll", () => {
+    const scroll = window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop || 0;
+    const backgroundBlur = document.getElementById(targetId);
+    backgroundBlur.style.opacity = scroll / 300;
+  });
+}
+
+backgroundBlur();