Recommended dependencies shouldn't be installed/activated on vanilla if they are Space Age mods

[QuingKhaos]

As the title. When a mod recommends a mod, that is gated as Space Age mod via feature flags, those shouldn't get installed/activated on vanilla only installations. Currently this happens and errors at load then. This is counter intuitive to the user.

[wanne]

This problem is more general: If
1. mod A requires mod B and
2. B recommends C but
3. C conflicts with A
installing (without even activating) A will result in in an startup error.
This is a horrible user interface! If your game is silently doing something it should never break anything.