Merge container logic into start.sh

This whole container thinking is over-engineered and we will get to
it if and when we need to.

setup/start/systemd/cloudron.target

@@ -0,0 +1,10 @@
+[Unit]
+Description=Cloudron Smartserver
+Documentation=https://cloudron.io/documentation.html
+StopWhenUnneeded=true
+Requires=box.service
+After=box.service
+# AllowIsolate=yes
+
+[Install]
+WantedBy=multi-user.target