Add tips from @beberlei blog post in the documentation

[fabpot]

I think that the information contained in the article written recently by @beberlei should be included somewhere in our docs.

http://www.whitewashing.de/2013/08/19/speedup_symfony2_on_vagrant_boxes.html

What do you think?

[weaverryan]

I like it a lot. We already have an open PR (#2760) about setting things up in Vagrant, and it's only been waiting for me because I want to try it out and validate it. I've ready @beberlei's post and it touches on issues I've seen people have. So, I think we should that information to #2760, and I'm happy to adapt it if Benjamin is ok with that.

[beberlei]

@weaverryan Of course, feel free to integrate anything from the blog into the documentation.

[javiereguiluz]

Closing it as "fixed" because the related article (https://symfony.com/doc/current/setup/homestead.html) already mentions Benjamin's tips for improved performance. Thanks!