build: update npm install command to use --legacy-peer-deps

This change modifies the build scripts to use --legacy-peer-deps flag when installing npm dependencies to resolve potential peer dependency conflicts during the build process. The change is applied to both bash (build.sh) and batch (build.bat) build scripts.

frontend/node_modules/wrappy/wrappy.js

@@ -0,0 +1,33 @@
+// Returns a wrapper function that returns a wrapped callback
+// The wrapper function should do some stuff, and return a
+// presumably different callback function.
+// This makes sure that own properties are retained, so that
+// decorations and such are not lost along the way.
+module.exports = wrappy
+function wrappy (fn, cb) {
+  if (fn && cb) return wrappy(fn)(cb)
+
+  if (typeof fn !== 'function')
+    throw new TypeError('need wrapper function')
+
+  Object.keys(fn).forEach(function (k) {
+    wrapper[k] = fn[k]
+  })
+
+  return wrapper
+
+  function wrapper() {
+    var args = new Array(arguments.length)
+    for (var i = 0; i < args.length; i++) {
+      args[i] = arguments[i]
+    }
+    var ret = fn.apply(this, args)
+    var cb = args[args.length-1]
+    if (typeof ret === 'function' && ret !== cb) {
+      Object.keys(cb).forEach(function (k) {
+        ret[k] = cb[k]
+      })
+    }
+    return ret
+  }
+}