Use tippy.js for context popup (#20393)

By appending the tooltips to `document.body`, we can avoid any stacking context issues caused by surrounding element's CSS.

This uses [tippy.js](https://github.com/atomiks/tippyjs) instead of Fomantic popups. We should aim to replace all Fomantic popups with this eventually and then get rid of the Fomantic `popup` module completely.

web_src/js/modules/tippy.js

@@ -0,0 +1,12 @@
+import tippy from 'tippy.js';
+
+export function createTippy(target, opts) {
+  return tippy(target, {
+    appendTo: document.body,
+    placement: 'top-start',
+    animation: false,
+    allowHTML: true,
+    arrow: `<svg width="16" height="7"><path d="m0 7 8-7 8 7Z" class="tippy-svg-arrow-outer"/><path d="m0 8 8-7 8 7Z" class="tippy-svg-arrow-inner"/></svg>`,
+    ...opts,
+  });
+}