Avoid circular dependency in build script

Use the node image and install docker onto it in the CI pipeline
building the builder image to avoid a circular dependency loop of
requiring the builder image in order to build it.

.forgejo/workflows/build.yaml

@@ -7,8 +7,23 @@ jobs:
   build:
     runs-on: docker
     container:
-      image: sif.g100.hornwitser.no:3000/furnavia/builder:latest
+      image: node:20-bookworm
     steps:
+      -
+        name: Install docker
+        run: |
+          apt-get update
+          apt-get install -y --no-install-recommends ca-certificates curl git
+          install -m 0755 -d /etc/apt/keyrings
+          curl -sSL https://download.docker.com/linux/debian/gpg -o /etc/apt/keyrings/docker.asc
+          chmod a+r /etc/apt/keyrings/docker.asc
+          echo \
+            "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] \
+            https://download.docker.com/linux/debian \
+            bookworm stable" \
+          > /etc/apt/sources.list.d/docker.list
+          apt-get update
+          apt-get install -y --no-install-recommends docker-ce-cli docker-buildx-plugin docker-compose-plugin
       -
         name: Get image tags
         id: info