Configure Webpack to make `@converse/headless` a library

Also, remove unused alias.

src/headless/package.json

@@ -2,10 +2,14 @@
   "name": "@converse/headless",
   "version": "10.1.0",
   "description": "Converse.js Headless build",
-  "author": "cmrd Senya <senya@riseup.net>",
+  "author": {
+    "name": "JC Brand",
+    "email": "jc@opkode.com"
+  },
+  "contributors": ["cmrd Senya <senya@riseup.net>"],
   "homepage": "https://conversejs.org",
   "license": "MPL-2.0",
-  "main": "dist/converse-headless.min.js",
+  "main": "dist/converse-headless.js",
   "module": "headless.js",
   "keywords": [
     "converse.js",

webpack/webpack.common.js

@@ -109,7 +109,6 @@ module.exports = {
         alias: {
             "IPv6":                     path.resolve(__dirname, "../node_modules/urijs/src/IPv6"),
             "SecondLevelDomains":       path.resolve(__dirname, "../node_modules/urijs/src/SecondLevelDomains"),
-            "formdata-polyfill":        path.resolve(__dirname, "../node_modules/formdata-polyfill/FormData"),
             "punycode":                 path.resolve(__dirname, "../node_modules/urijs/src/punycode"),
             "./shims":                  path.resolve(__dirname, "../src/strophe-shims.js"),
         }

webpack/webpack.headless.js

@@ -11,8 +11,13 @@ module.exports = merge(common, {
     output: {
         path: path.resolve(__dirname, '../src/headless/dist'), // Output path for generated bundles
         filename: "[name].js",
-        chunkFilename: '[name].js'
+        chunkFilename: '[name].js',
+        globalObject: 'this',
+        publicPath: '',
+        library: {
+            name: 'converse',
+            type: 'umd',
+        },
     },
     mode: "production",
 });
-