refactor: new dev/testing environment

[apricote]

• Add a new development environment based on github.com/hetznercloud/kubernetes-dev-env
• Refactor the Robot test server to be re-installed once a week and use overlayrootfs for clean disk on every run

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 77.77778% with 2 lines in your changes missing coverage. Please review.

Project coverage is 72.18%. Comparing base (8656812) to head (775cbc7).

Files	Patch %	Lines
tests/e2e/testing.go	77.77%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #671 +/- ## ========================================== + Coverage 71.89% 72.18% +0.28% ========================================== Files 32 32 Lines 2658 2653 -5 ========================================== + Hits 1911 1915 +4 + Misses 556 550 -6 + Partials 191 188 -3 ```

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[jooola]

We are also missing a reset triggered at the end of the pipeline. Happy to only implement it in a later PR.