Setup kubectl so it never expires

Created by: Tirokk

Authored by roschaefer Apr 3, 2019 Merged Apr 4, 2019

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Install everything on Travis CI through snap

This commit should setup kubectl in a way that it downloads a recent
`kubeconfig` from Digitial Ocean with `doctl`. Thus, deployments will
not fail after a kubeconfig has expired.

Since it seems to be the recommended way to install `doctl` through
[Snap](https://snapcraft.io/). I decided to install everything else
through snap too, including chrome and docker.

Pullrequest

Issues

• fixes #344 (closed)

Checklist

• Env-Variables adjustment needed

How2Test

• You have to add DOCTL_ACCESS_TOKEN as encrypted env var on Travis CI settings