[K8s] Reworking 8s networking, especially for local connectivity service case

[MRiganSUSX]

Description

!!! Requires DUNE-DAQ/daqsystemtest#244 !!!

Fixes part of #583.

This PR refactors the Kubernetes networking model. The previous approach, which relied on a manually managed kubectl port-forward subprocess and a socat proxy sidecar, has been replaced with a NodePort service and hostAliases.

Key Changes:
Replaced port-forward with a NodePort Service.
Now: The connection server pod is exposed via a standard Kubernetes NodePort service. This is the idiomatic way to expose a service to external traffic and is managed entirely by the Kubernetes cluster.

Replaced Proxy Sidecar with hostAliases.
Now: The sidecar has been removed. Pods now use the spec.hostAliases field to resolve localhost directly to the ClusterIP of the connection server's service. This is a more lightweight and direct networking approach.

Dynamic Port Extraction:
The connection server port is no longer a fixed configuration value. It is now dynamically extracted from the gunicorn command arguments in the BootRequest.

Code Simplification:
Removed all code related to managing the port-forward subprocess, including starting the process, monitoring its output, and ensuring it's killed correctly.

Removed the logic for injecting the sidecar container into pod manifests.
Removed configuration options like sidecar_image and port_forward_timeout that are no longer needed.

Type of change

• Documentation (non-breaking change that adds or improves the documentation)
• New feature (non-breaking change which adds functionality)
• Optimization (non-breaking, back-end change that speeds up the code)
• Bug fix (non-breaking change which fixes an issue)
• Breaking change (whatever its nature)

Key checklist

• All tests pass (eg. python -m pytest)
• Pre-commit hooks run successfully (eg. pre-commit run --all-files)

Further checks

• Code is commented, particularly in hard-to-understand areas
• Tests added or an issue has been opened to tackle that in the future.
  (Indicate issue here: # (issue))

[wanyunSu]

Tested with MSQT, LGTM