Webpack 4 (WIP) (#12098)

* Webpack 4

* webpack: force angular version 1.6 as 1.7 has removed a legacy feature toggle Grafana needs, switched from awesome-typescript-loader to ts-loader & forked ts checker

* Webpack 4

* webpack: force angular version 1.6 as 1.7 has removed a legacy feature toggle Grafana needs, switched from awesome-typescript-loader to ts-loader & forked ts checker

* upgrade ts loader

* simplified splitChunks

* upgrade circle node image to v8

* webpack: minor changes, using the new mode option, removed unused awesome-typescript loader, investigating karma issue but no solution yet

* fix: change angular mocks version restriction to be more strict

* add babel-loader for HMR support, fix karma debug runner

* babel-loader to yarn.lock

* webpack: changed from ExtractTextPlugin  to MiniCssExtractPlugin, and updated the minification step to use new webpack4 optimization config section

* webpack: remove css minifcation from general css processing as it's done in the webpack optimization step

* limit vendors chunk to .ts and .js files

* fix: removed typescript compile error, wanted to see if we still got test failure for that

* tech: upgrade uglify-js, should be faster now

scripts/webpack/webpack.common.js

@@ -1,5 +1,5 @@
 const path = require('path');
-const { CheckerPlugin } = require('awesome-typescript-loader');
+const ForkTsCheckerWebpackPlugin = require('fork-ts-checker-webpack-plugin');
 
 module.exports = {
   target: 'web',
@@ -61,6 +61,8 @@ module.exports = {
     ]
   },
   plugins: [
-    new CheckerPlugin(),
+    new ForkTsCheckerWebpackPlugin({
+      checkSyntacticErrors: true,
+    }),
   ]
 };