Support KNP Menu

[tacman]

AdminLTEBundle supported KnpMenu, which was nice. It's a powerful library.

I see that the key for knp_menu support is in the config, but if it's enabled it fails, because knp-menu.yml is missing from the config.

I've added that file, but of course the rendering doesn't work. @kevinpapst , is that something you can bring over from the old bundle? Especially since it looks like we should have vertical menu support soon.

[kevinpapst]

If someone wants to provide the code via PR 🎉 I don't mind testing and merging it. It seems to be a well known and wide spread package... But I don't use it and have no need for it, so I will not put my time into it.

[eerison]

But the question is, can we add this without add knp menu as dependency?

[eerison]

I think it's:)

https://github.com/kevinpapst/AdminLTEBundle/blob/master/composer.json

[kevinpapst]

Yes, would go into require-dev

Edit: ups, you were quicker