Merge infra and k3 into one directory again

Since I don't have multiple terraform steps anymore it simply doesn't
make sense to me anymore to split all tasks into separate folders.
Instead I try to be as clear as possible in the README to make it easy
to follow the structure in the future without too much headache.

modules/hetzner/dns/variables.tf

@@ -0,0 +1,19 @@
+variable "zone" {
+  type = string
+}
+
+variable "zone_ttl" {
+  type = number
+  default = 3600
+}
+
+variable "records" {
+  type = set(object({
+    name = string
+    value = string
+    type = string
+    ttl = optional(number, null)
+  }))
+  default = []
+}
+