Change Bake templates to be view based

This is a little rough around the edges, but aught to be good enough to now discuss.

The main functional benefit introduced here is that php tags in a bake template are treated as plain text. I.e. whereas before a template looked like this:

    echo "<?php\n"; ?>
    namespace <?= $namespace ?>\Controller\Component;

Now, by using a different tag pair to indicate template logic, it would look like this:

    <?php
    namespace <%= $namespace %>\Controller\Component;

I haven't fully converted the existing [template templates](https://github.com/AD7six/cakephp/tree/3.0-bake-view/src/Template/Bake/Template), apart from just cleaning them up there's the opportunity to move any of the ugly logic into a helper/element to simplify things (either in this PR or at any point in the future).
I don'r really want to add an option for that, but - *do* we want the template to be cleaned up?

It is quite useful to do this:

```
-> cat /tmp/Bake-config-routes-ctp.php
<af77ba42a2cb35d9cf94f69370a316e21f6bd75f
/**
 * These are my routes. There are many like them but these are my own.
 */
use Cake\Routing\Router;

Router::plugin('<?= $plugin ?>', function($routes) {
	$routes->fallbacks();
});
```

To see how [a bake template](https://github.com/AD7six/cakephp/blob/3.0-bake-view/tests/test_app/Plugin/TestBakeTheme/src/Template/Bake/config/routes.ctp) is rewritten - even after the fact.