chore: set cors config to webpack

Dockerfile

 FROM theiaide/theia-java:1.3.0
 
+COPY webpack.config.js /home/theia/webpack.config.js
 COPY plugins /home/plugins
 
 ENTRYPOINT [ "yarn", "theia", "start", "/home/project", "--hostname=0.0.0.0", "--plugins=local-dir:/home/plugins"]

webpack.config.js

+/**
+ * This file can be edited to customize webpack configuration.
+ * To reset delete this file and rerun theia build again.
+ */
+// @ts-check
+const config = require('./gen-webpack.config.js');
+
+config.devServer: {
+  headers: {
+    "Access-Control-Allow-Origin": "*",
+    "Access-Control-Allow-Methods": "GET, POST, PUT, DELETE, PATCH, OPTIONS",
+    "Access-Control-Allow-Headers": "X-Requested-With, content-type, Authorization"
+  }
+}
+
+/**
+ * Expose bundled modules on window.theia.moduleName namespace, e.g.
+ * window['theia']['@theia/core/lib/common/uri'].
+ * Such syntax can be used by external code, for instance, for testing.
+config.module.rules.push({
+    test: /\.js$/,
+    loader: require.resolve('@theia/application-manager/lib/expose-loader')
+}); */