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/inflight/inflight.js

@@ -0,0 +1,54 @@
+var wrappy = require('wrappy')
+var reqs = Object.create(null)
+var once = require('once')
+
+module.exports = wrappy(inflight)
+
+function inflight (key, cb) {
+  if (reqs[key]) {
+    reqs[key].push(cb)
+    return null
+  } else {
+    reqs[key] = [cb]
+    return makeres(key)
+  }
+}
+
+function makeres (key) {
+  return once(function RES () {
+    var cbs = reqs[key]
+    var len = cbs.length
+    var args = slice(arguments)
+
+    // XXX It's somewhat ambiguous whether a new callback added in this
+    // pass should be queued for later execution if something in the
+    // list of callbacks throws, or if it should just be discarded.
+    // However, it's such an edge case that it hardly matters, and either
+    // choice is likely as surprising as the other.
+    // As it happens, we do go ahead and schedule it for later execution.
+    try {
+      for (var i = 0; i < len; i++) {
+        cbs[i].apply(null, args)
+      }
+    } finally {
+      if (cbs.length > len) {
+        // added more in the interim.
+        // de-zalgo, just in case, but don't call again.
+        cbs.splice(0, len)
+        process.nextTick(function () {
+          RES.apply(null, args)
+        })
+      } else {
+        delete reqs[key]
+      }
+    }
+  })
+}
+
+function slice (args) {
+  var length = args.length
+  var array = []
+
+  for (var i = 0; i < length; i++) array[i] = args[i]
+  return array
+}