Node-Installer job with init container

[voigt]

What:

• an init-container should take care of downloading spin-shim (and potentially all the other shims) to a directory /assets
• node installer finds shim in /assets directory to install shim

Why

• this removes the responsibility of downloading shim from node-installer and makes it pluggable

Todos

• Create Image for Node-Installer
• Create Image for Spin-Shim Downloader (shell script for download enough?)
• Configure Mount Volumes Accordingly