Add cache panel to the web profiler

[skalpa]

This will enable the cache panel once silexphp/Silex#1524 gets merged and symfony 3.3 is released.

I had to add @dev entries to composer.json so composer would run, I'll update the file when 3.3 is ready.

I also had to check if symfony/web-profiler-bundle >= 3.3 was available:

As profiler.templates_path was registered as a lazy/dynamic parameter and I didn't want to initialize anything lazy at this stage, I changed its definition and made it a regular parameter.

If you don't like this I could change it back, but that means we'll have to do something like the following instead 😢 :

if (isset($app['cache.pools']) && class_exists('Symfony\Component\Cache\DataCollector\CacheDataCollector')) {
    $app->extend('cache.pools', function ($pools) {
        if (is_file($app['profiler.templates_path'].'/Collector/cache.html.twig')) {
            // ...
        }

        return $pools;
    });
    $app->extend('data_collector.templates', function ($templates) {
        if (is_file($app['profiler.templates_path'].'/Collector/cache.html.twig')) {
            // ...
        }

        return $templates;
    });
    $app->extend('data_collectors', function ($collectors) {
        if (is_file($app['profiler.templates_path'].'/Collector/cache.html.twig')) {
            // ...
        }

        return $collectors;
    });
}