feat(ci): replace npmci with szci across CI and images; add szci preinstalled images and make tini the PID 1 init in Docker images

test/test_szci.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+set -e
+
+# check if szci is available
+npm init -y
+szci -v
+
+# TODO update szci to not require package.json
+szci node install stable
+
+# check if npm picks it up
+szci command pnpm install -g @gitzone/tsrun
+szci command tsrun -v