Panel edit: Add feature to drag & drop spreadsheet files to the grafana datasource (#60586)

Co-authored-by: Oscar Kilhed <oscar.kilhed@grafana.com>
Co-authored-by: Christopher Moyer <35463610+chri2547@users.noreply.github.com>
Co-authored-by: Adela Almasan <adela.almasan@grafana.com>

public/app/core/utils/sheet.ts

@@ -0,0 +1,12 @@
+import { read, utils } from 'xlsx';
+
+import { ArrayDataFrame, DataFrame } from '@grafana/data';
+
+export function readSpreadsheet(file: ArrayBuffer): DataFrame[] {
+  const wb = read(file, { type: 'buffer' });
+  return wb.SheetNames.map((name) => {
+    const frame = new ArrayDataFrame(utils.sheet_to_json(wb.Sheets[name]));
+    frame.name = name;
+    return frame;
+  });
+}