The Google analytics key configuration should also support the target-environment attribute

[michaelwechner]

The Google analytics is configurable per real, e.g.

src/realms/yanel-website/data-repo/data/google-analytics-key-config.xml

In order to prevent tracking on development environment, we replace the real key by some dummy key, but the problem is that one needs to make sure that on the productive environment the key is actually set