Create a list method for the wep app to return all the packages

[yannickglt]

This method would allow to get all the packages available on the local registry.

[rlidwka]

What is it used for, and what does it have to do with web app?

[yannickglt]

The purpose of this method is to be used with an external system. In my case, the method will be requested by a yeoman generator to suggest the user to use a package available on our internal registry to quickly bootstrap new projects.
I moved the method from the wep app to the api app. It makes more sense as it is an equivalent of the index page of the web app but for the API.

[rlidwka]

Maybe /-/all?local would be better? We already have that for search, and "local" option would be easy to add.

[yannickglt]

Ok good idea. That is done on my last commit.

[rlidwka]

Squashed and merged in ea50f3d, thanks!