Move infra-setup and k3s-setup into dedicated directories

This changes makes it easier to differentiate and understand the
different parts of the kubernetes setup. On one hand we have the bare
infrastructure (servers, network, etc), on the other hand we have the
software (k3s in this case).

In the future we'll have a few more parts, like the minimal
configuration of the kubernetes cluster, e.g. with a cert-manager. This
is easier to manage with helm or terraform than with ansible. Therefore
it makes even more sense to split the responsibilities into dedicated
directories.

README.adoc

@@ -11,36 +11,36 @@ The setup is split into 2 dedicated parts:
 
 . Ensure `terraform` is installed
 . Ensure `ansible` is installed
-. Create `config.auto.tfvars` with all the needed configuration-secrets (Stored in password-manager)
 
 == Setup
 
-In most cases it should be save to follow this guide:
+The project is split into different directories, each responsible for another task.
+For the initial setup it is mandatory to follow the instructions of each directory in the following order.
+Subsequent changes may only require a subset of these instructions.
+Though, it should be safe to run each step multiple times, they should all be indempotent.
 
-[source,bash]
-----
-ansible-galaxy install -r requirements.yml # <1>
-terraform apply # <2>
-ansible-playbook k3s.orchestration.site -i inventory.ini # <3>
-ansible-playbook download-kube-config.yml -i inventory.ini # <4>
-ansible-playbook k3s.orchestration.upgrade -i inventory.ini # <5>
-----
+=== infra
 
-<1> Install required ansible collections to create a k3s-cluster (can be omitted in subsequent runs)
-<2> Setup infrastructure and create/update inventory.ini (This might take some time, even after it's "ready")
-<3> Install k3s
-<4> Download the kube-config to .kube/config
-<5> Update k3s when necessary
+Run this setup in the `infra/` directory.
 
-[IMPORTANT]
-Step 4 will override any existing kube config this might destroy any existing settings!
+include::infra/README.adoc[tag=setup]
+
+=== k3s
+
+Run this setup in the `k3s/` directory.
+
+[NOTE]
+The k3s-setup requires a `inventory.ini` which is automatically created by the infra.
+So, make sure to apply the infra at least once, before running these playbooks.
+
+include::k3s/README.adoc[tag=setup]
 
 == Enlarge / Reduce size of cluster
 
 Increase::
 --
-. Simply adjust the number of agents/servers in your `config.auto.tfvars`.
-. Run steps 2 & 3 of the setup again
+. Simply adjust the number of agents/servers in your `infra/config.auto.tfvars`.
+. Run steps 3 & 4 of the setup again
 --
 Decrease::
 --
@@ -55,8 +55,7 @@ Instead proceed as the following:
 
 == Responsibilities
 
-The terraform scripts are responsible for:
-
+`infra/`::
 * Creation of network for the kubernetes-cluster
 ** A public subnet exposed to the internet for the kubernetes-servers
 ** A private subnet for the kubernetes-agents
@@ -72,8 +71,7 @@ The terraform scripts are responsible for:
 * Setup SSH-connections
 * Creating DNS-records in Hetzer Cloud
 
-The ansible scripts are responsible for:
-
+`k3s/`::
 * Installing k3s
 * Keep the software up-to-date