Configure Kind in Gitlab to allow kubernetes injection tests to run

[randomanderson]

Motivation

Previously, the kubernetes injection tests ran in Github Actions. With the move to one-pipeline, these tests need to run in Gitlab. Running Kind in gitlab doesn't work without the right incantations.

Changes

• Using the correct ports/ip addresses for the build container to talk to the kind container
• Running kind in the bridge network instead of the kind network. Only the bridge network can communicate with the internet
• Changing execute_command to use shlex because the previous command.split() broke on any complicated command.

There were hundreds of variations and commits attempted to get this final solution. While there are only ~100 lines changed in this PR, there were months of work behind it

Reviewer checklist

• If PR title starts with [<language>], double-check that only <language> is impacted by the change
• No system-tests internal is modified. Otherwise, I have the approval from R&P team
• CI is green, or failing jobs are not related to this change (and you are 100% sure about this statement)
• A docker base image is modified?
  • the relevant build-XXX-image label is present
• A scenario is added (or removed)?
  • Get a review from R&P team

[robertomonteromiguel]

Thanks Laplie!! Update your branch before merge, because there are some changes in the k8s lib injection that are not present on this PR. Probably you need to make some tweaks on the new tests (configure port and host)