all: move ng dependencies and rxjs dependency in the root of the project

[SuperITMan]

I'm submitting a...

[ ] Regression (a behavior that used to work and stopped working in a new release)
[ ] Bug report  
[X] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead see https://github.com/NationalBankBelgium/stark/blob/master/CONTRIBUTING.md#got-a-question-or-problem

Current behavior

In stark-ui, stark-core, ... we have devDependencies for @angular/* and for rxjs. (those packages have to be installed by the application itself)

Expected behavior

Instead of installing multiple times @angular deps in each package, we should install them in the ROOT of project and add paths to them in every package.

What is the motivation / use case for changing the behavior?

Improving the project