Consolidate Server Port Variable Definitions

[Nana-EC]

Story Form

As a block node operator
I want to consolidate the number of location in the code where the ports are specified
So that there is a cleaner, efficient and common mechanism for port configuration for the server

Technical Notes

In PR #805 a single change to set the new default port for Helidon and Prometheus resulted in a lot of file needing to be changed.
This covered configs at the JVM, docker and k8s levels. It was also made more complex by the Simulator runs.
Preferably we'd have them in 1 or very few places so operators can easily customize it.

A single environment variable location would be preferred

[hendrikebbers]

@AlfredoG87 is this a good first issue that a newcomer could solve? If yes, can you help us by following our new guidelines at https://github.com/hiero-ledger/governance/blob/main/guidelines/good-first-issues.md