The navigation through a bunch of config files, all with just a few
lines in it is cumbersome. This change moves all the configuration into
a centralized `config.ini` that way it's easier for me to get a quick
overview of the setup. The `config.ini` acts as another inventory and is
therefore references as such by the ansible.cfg. The `inventory.ini`
(which is generated by terraform in the provisioning-step) is not
affected by this change.
With this change we no longer use user-data scripts on the provided
machines. That makes it way easier for me to handle all the
configuration, since I only have to run ansible. Furthermore this the
burdon to think what may went wrong, since ansible is easier to debug
than some arbitrary scripts which run at provisioning-time on the
machines.
With this change I should also think about restructuring the code a bit
as well. Since it's actually easier to provide the initial
software-stack for the cluster via ansible than via terraform, at least
as far as I can tell right now.
