[WIP] Google Analytics UID in webspace config

Define analytics key in url in webspace

__Tasks:__

- [ ] test coverage
- [ ] gather feedback for my changes
- [ ] submit changes to the documentation
- [ ] add feature #585 


__Informations:__

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| Tests pass?   |