Replace closure compiler plugin with official one

Replace webpack-closure-compiler (deprecated) with closure-webpack-plugin,
which is official closure plugin.
Also, reworked CI.

webpack.config.js

@@ -1,89 +1,4 @@
-const path = require('path');
-const os = require('os');
-const ClosureCompilerPlugin = require('webpack-closure-compiler');
-const HtmlWebpackPlugin = require('html-webpack-plugin');
-const CopyWebpackPlugin = require('copy-webpack-plugin');
-const { CleanWebpackPlugin } = require('clean-webpack-plugin');
-const webpack = require('webpack');
-var webpackMode;
-
-function makeClosureCompiler() {
-    const externDir = path.join(__dirname, "externs");
-    const externs = [
-        path.join(externDir, "googleAnalytics.js"),
-        path.join(externDir, "performance.js"),
-        path.join(externDir, "webassembly.js")
-    ];
-
-    var pluginOptions = {
-        compiler: {
-            compilation_level: "ADVANCED",
-            create_source_map: true,
-            externs: externs
-        },
-        concurrency: os.cpus().length
-    };
-
-    if (process.env.CLOSURE_PATH) {
-        pluginOptions.compiler.jar = process.env.CLOSURE_PATH;
-    }
-
-    return new ClosureCompilerPlugin(pluginOptions);
-}
-
-var plugins = [
-    new CleanWebpackPlugin(),
-    new CopyWebpackPlugin([
-        {
-            from: 'assets/bootstrap.min.css',
-            to: 'assets/'
-        }
-    ]),
-    new webpack.DefinePlugin({
-        GOOGLE_ANALYTICS_TAG: JSON.stringify(process.env.GOOGLE_ANALYTICS_TAG)
-    }),
-    new HtmlWebpackPlugin({
-        minify: {
-            collapseWhitespace: true,
-            conservativeCollapse: true,
-            removeComments: true
-        },
-        inject: true,
-        template: 'html/index.html'
-    })
-];
-
-if (process.env.PRODUCTION) {
-    plugins.push(makeClosureCompiler());
-    webpackMode = "production";
-} else {
-    webpackMode = "development";
-}
+const { getWebpackConfig } = require('./webpack.base');
 
 
-module.exports = {
-    entry: "./src/ui.ts",
-    output: {
-        filename: "assets/bundle.[hash].js",
-        path: path.join(__dirname, "dist")
-    },
-    plugins: plugins,
-    devtool: "source-map",
-    devServer: {
-        contentBase: path.join(__dirname, "dist"),
-        port: 9000
-    },
-    resolve: {
-        extensions: ['.ts', '.tsx', '.js']
-    },
-    mode: webpackMode,
-    module: {
-        rules: [
-            {
-                test: /\.ts$/,
-                exclude: /node_modules/,
-                use: [{loader: 'ts-loader', options: {transpileOnly: true}}]
-            }
-        ]
-    }
-}
+module.exports = getWebpackConfig(process.env.PRODUCTION, process.env.GOOGLE_ANALYTICS_TAG);