Build sal-scripts image (#15)

This will make it easier to distribute changes in a coherent manner.

.github/workflows/ci.yml

@@ -0,0 +1,18 @@
+name: CI
+on:
+  push:
+    branches:
+      - main
+      - r[1-9]
+  pull_request:
+    branches:
+      - main
+      - r[1-9]
+jobs:
+  build-and-push-sal-scripts:
+    name: Build and push sal-scripts
+    uses: eu-nebulous/github-actions/.github/workflows/build-and-push-container-image.yml@main
+    with:
+      context: .
+      image-name: sal-scripts
+    secrets: inherit

Dockerfile

@@ -0,0 +1,6 @@
+FROM busybox:1.36.1-musl
+
+COPY installation-scripts /sal-scripts/installation-scripts
+COPY installation-scripts-onm /sal-scripts/installation-scripts-onm
+COPY k8s /sal-scripts/k8s
+COPY serverless /sal-scripts/serverless