Improved ref switcher dropdown performance

What does this MR do?

Removes jQuery creating elements, instead uses vanilla JS to create elements. This increase the performance significantly, previously with ~500 branches render time was approx. 30ms, with this change it dropped down to approx. 5ms.

The JSON now returns a maximum of 100 branches & 100 tags. The user can then search for more if they require.

What are the relevant issue numbers?

Closes #18202 (closed)

app/assets/javascripts/project.js

@@ -90,7 +90,7 @@
             } else {
               var link = refLink.cloneNode(false);
-              if (ref.name === selected) {
+              if (ref === selected) {
                 link.className = 'is-active';
               }