Add exoscale and kubernetes support

[zugao]

Summary

• Added improvements to the CLI
• Updated the k8s client to work with typed objects
• Simplified the business logic
• Fixed logging setup

This PR is configured to be merged into invoice branch which means it's easier to review what changes have been done to the latest version of this POC. Ultimately this PR will be merged into master.

Test:

• A manual test can be done, just add cluster file with as may entries server=token as you want.

Later:

• Documentation will be added in a subsequent PR
• Writing to the DB will be done in a subsequent PR

Checklist

• Categorize the PR by setting a good title and adding one of the labels:
  bug, enhancement, documentation, change, breaking, dependency
  as they show up in the changelog

[Kidswiss]

Something is weird with the logging configuration.

Most log calls use V(1) or V(2), but the default seems to be running with 0. It currently only prints errors. Also the log-level flag isn't actually used, but there's a debug flag in the code that can't be set.

[ccremer]

I'm not sure I spotted all the locations, but I suggest you have a look at error handling again