Clean up installer and prepare it for production use

Astraea

The installer is currently offering options for "configuration only" and "bootstrap" servers. These were mostly for debugging and testing. Now that we have proper documentation, these steps can go, and the whole configuration-only flow can be removed, cleaning up the installer tremendously.

Astraea

This has been done in: https://git.honse.farm/astraea/honse-farm/-/merge_requests/62

Removed "bootstrap server" installation
Removed "configuration only" installation (we have docker-compose examples for those now)
Add a nice intro pointing server owners to documentation for custom setups.