Rewrite web front-end using React

This is a big commit, some font-end function are still working,
including manage, error handle, as others.

web/src/component/Common.js

@@ -0,0 +1,40 @@
+export function CalcReadableFilesize(filesize) {
+  if (filesize < 1024) {
+    return filesize;
+  }
+  if (filesize < 1024 * 1024) {
+    return Math.round(filesize / 1024) + "K";
+  }
+  if (filesize < 1024 * 1024 * 1024) {
+    return Math.round(filesize / 1024 / 1024) + "M";
+  }
+  if (filesize < 1024 * 1024 * 1024 * 1024) {
+    return Math.round(filesize / 1024 / 1024 / 1024) + "G";
+  }
+}
+
+export function CalcReadableFilesizeDetail(filesize) {
+  if (filesize < 1024 * 1024) {
+    return filesize;
+  }
+  if (filesize < 1024 * 1024 * 1024) {
+    return numberWithCommas(Math.round(filesize / 1024)) + "K";
+  }
+  if (filesize < 1024 * 1024 * 1024 * 1024) {
+    return numberWithCommas(Math.round(filesize / 1024 / 1024)) + "M";
+  }
+  if (filesize < 1024 * 1024 * 1024 * 1024 * 1024) {
+    return numberWithCommas(Math.round(filesize / 1024 / 1024 / 1024)) + "G";
+  }
+}
+
+function numberWithCommas(x) {
+  x = x.toString();
+  var pattern = /(-?\d+)(\d{3})/;
+  while (pattern.test(x)) x = x.replace(pattern, "$1,$2");
+  return x;
+}
+
+export function SayHello() {
+  return "Hello";
+}