Change to use non-static IKubernetesConfiguration class

[APErebus]

Background

The KubernetesConfig is a static file that reads configuration for the Kubernetes Agent. Being static makes this hard to test/mock.

Results

This PR introduces the IKubernetesConfiguration and the implementation EnvironmentKubernetesConfiguration.

It also changes how we detect we are running as a Kubernetes agent with the new IKubernetesAgentDetection and KubernetesAgentDetection

How to review this PR

Quality ✔️

Pre-requisites

• I have read How we use GitHub Issues for help deciding when and where it's appropriate to make an issue.
• I have considered informing or consulting the right people, according to the ownership map.
• I have considered appropriate testing for my change.