Kartongips - a kubecfg fork

This is Kartongips - a hscloud-specific kubecfg fork. It aims to let us implement features like:

• secret management
• multi-cluster support
• persistent diff-against-production (a.k.a. 'ultrakubediff').

Fork technicalities

We forked off from github.com/q3k/kubecfg at commit b6817a94492c561ed61a44eeea2d92dcf2e6b8c0.