Dockerize app, and k8s

reduce lib installed, collect static during build

• keep app and test related libs but remove sphinx and django-extensions related dependencies.
• remove apache2-dev
• collect static, and get ready to copy it on startup if needed to be serve by another container
• gunicorn only reload when used in docker-compose
• none root user
• run migration on startup
• copy static files to $STATIC_ROOT_ON_STARTUP_COPY when mounted
• add helm chart
• use PostgreSQL from zolando

Closes #271 Closes #272

chart/templates/NOTES.txt

+# Application will be available at http{{ if $.Values.ingress.tls }}s{{ end }}://{{ .Values.ingress.host.name }}
+
+# To delete app, do:
+helm delete {{.Release.Name}}
+kubectl delete pvc -lapp.kubernetes.io/name=postgresql
+kubectl delete pvc -lapp.kubernetes.io/name=redis
+
+# You also can delete media dir:
+kubectl delete pvc -lapp.kubernetes.io/name=django
\ No newline at end of file