Adds handlebar plugin to webpack build

[onedotover]

This pull request is in reference to #1544. If we bring back the ability to access environment variables, we have two main benefits.

Easier Upgrade Path
Users upgrading to the webpack version will have less difficulty if they are already taking advantage of the handlebar template logic.

Environment Specific index.html
Users can take advantage of multiple environments. I believe these are examples of typical needs for environment specific logic.

<base href={{environment.baseURL}} />

...

{{#if environment.production}}
  <script type="text/javascript">
    // Google Analytics
    (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
    (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
    m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
    })(window,document,'script','https://www.google-analytics.com/analytics.js','ga');

    ga('create', 'UA-########-#', 'auto');
  </script>
{{/if}}

...

  <script type="text/javascript">
    // Load Facebook SDK for JS
    window.fbAsyncInit = function () {
      FB.init({
        appId: "{{environment.facebookAppId}}", // Test app vs Production app
        cookie: true,
        xfbml: false,
        version: "v2.7"
      });
    };
    (function (d, s, id) {
      var js, fjs = d.getElementsByTagName(s)[0];
      if (d.getElementById(id)) {
        return;
      }
      js = d.createElement(s);
      js.id = id;
      js.src = "//connect.facebook.net/en_US/sdk.js";
      fjs.parentNode.insertBefore(js, fjs);
    }(document, "script", "facebook-jssdk"));
  </script>

Webpack Dev Server Base URL
Webpack Dev Server has an issue with baseURL: webpack/webpack-dev-server#288 By making this environment specific, users who need a nested directory structure for their SPA can use a baseURL of / for local testing using webpack dev server, but have a different value for production.

Build System Independent
There is actually a way to use variables from the HTML Plugin currently used in the form <%= htmlWebpackPlugin.options.title %>. However, this makes the templates build system specific. If you wanted to change away from Webpack later, these would not longer apply. By using handlebars, you can move between build systems.

This can also help address the following issues:
#1509
#1460
#1064

[filipesilva]

As mentioned in #1544 (comment), this functionality was never intended and we have removed it. As such we are not looking for PRs to add it back.

[onedotover]

Ah bummer. Ok well thanks for looking at this. I appreciate what you guys have done with Angular CLI! It's great!

[niklas-dahl]

Since this is closed, is there a diffrent way to archive this?

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}