[ENHANCEMENT] added methods to retrieve portals and urls from WebspaceManager

__Tasks:__

- [x] test coverage
- [ ] gather feedback for my changes


__Informations:__

| Q             | A
| ------------- | ---
| Tests pass?   | yes
| Fixed tickets | none
| BC Breaks     | none
| Doc           | none
We should rather inject this into the container if this is the same environment variable as given by the AppKernel.

As each dependencyinjection container is scoped to an environment, and this class is a service, then it will always be passed the same environment.