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/README.md

@@ -0,0 +1,37 @@
+# inflight
+
+Add callbacks to requests in flight to avoid async duplication
+
+## USAGE
+
+```javascript
+var inflight = require('inflight')
+
+// some request that does some stuff
+function req(key, callback) {
+  // key is any random string.  like a url or filename or whatever.
+  //
+  // will return either a falsey value, indicating that the
+  // request for this key is already in flight, or a new callback
+  // which when called will call all callbacks passed to inflightk
+  // with the same key
+  callback = inflight(key, callback)
+
+  // If we got a falsey value back, then there's already a req going
+  if (!callback) return
+
+  // this is where you'd fetch the url or whatever
+  // callback is also once()-ified, so it can safely be assigned
+  // to multiple events etc.  First call wins.
+  setTimeout(function() {
+    callback(null, key)
+  }, 100)
+}
+
+// only assigns a single setTimeout
+// when it dings, all cbs get called
+req('foo', cb1)
+req('foo', cb2)
+req('foo', cb3)
+req('foo', cb4)
+```