Move user account validation from controller to request classes

[euantorano]

Looks good to me 😄

I think we need to discuss how we write validation rules at some point. I personally prefer the array syntax, for example:

'name' => ['required', 'min:3'],

Instead of:

'name' => 'required|min:3',

This doesn't stop us merging, but we should probably agree on one format and stick to it :)

I'm also not 100% sure the array syntax works in Laravel 5.3, but I think it does. It's not documented in their documentation at all.