Add PHP CS fixer for this application

[bocharsky-bw]

Resolve #395.

[javiereguiluz]

@bocharsky-bw thanks for working on this!

I have two questions:

1. Is it recommended to add PHP-CS-Fixer as a project dependency or is it better to install it as a global tool in your computer?

2. Which is the default list of fixers applied when you don't select any config? I've seen some fixers in the official docs that are interesting but I don't know if they are enabled. For example: phpdoc_order, short_array_syntax, ordered_use, etc.

[bocharsky-bw]

Hey @javiereguiluz

1. Actually, I don't know, but I did the same way as we had done with PhpUnit. I wonder others opinion about it.

2. As I see in docs:

By default, all PSR-2 fixers and some additional ones are run.

So I specified Symfony level explicitly and added a few fixers from Contrib level that you had suggested.

[javiereguiluz]

@bocharsky-bw very nice! Thanks. Let's wait for others opinion about adding PHP-CS-Fixer as a dependency or not.

[javiereguiluz]

@bocharsky-bw you did a great work here. Thank you! I'm merging it because we can always tweak this config later to add/remove more fixers if needed.