ui: add layouts and layout classes

[dsebastien]

Integrate our layout classes and utility classes

[christophercr]

Discussing with Julien, he mentioned that this could be completely replaced by https://github.com/angular/flex-layout in the client apps.

In fact there is already an issue created for this: #668.

We need to discuss whether this is the approach we want to follow or to keep using the stark layout classes as before.

[christophercr]

After discussing this with @cnomes, we've decided not to implement the layout classes from the old Stark but to suggest using the new https://github.com/angular/flex-layout library.