drop(koolbox): Remove terraform from koolbox in favour of opentf

images/koolbox/Dockerfile

@@ -118,8 +118,6 @@ RUN curl -L "https://github.com/rust-lang/mdBook/releases/download/${MDBOOK_VERS
     && install -o root -g root -m 0755 mdbook /usr/local/bin/mdbook
 
 # Terraform CLI
-FROM docker.io/hashicorp/terraform:1.5.3 AS terraform
-
 FROM quay.io/shivering-isles/opentf:0.1.0 as opentf
 
 # Actual start of container build