Require certain namespaces to always use the same alias

[TravisCarden]

I want specific classes to always be aliased with the same names. For example, I want these classes to always and only be aliased like this:

use Symfony\Component\Filesystem\Filesystem as SymfonyFilesystem;
use Symfony\Component\Process\Process as SymfonyProcess;

Never like this, for example:

use Symfony\Component\Filesystem\Filesystem; # No alias.
use Symfony\Component\Process\Process as SomeNonStandardAlias;

I looked over https://github.com/slevomat/coding-standard/blob/master/doc/namespaces.md and didn't find anything that does this. If I'm not overlooking one, would you consider adding it? I would be willing to help with a PR--though I only consider myself an "advanced beginner" with writing rules, so I might need some direction to write one well (and add tests?).