Draft: Re-organize platform POMs for building, staging, assembly, and tooling support

[GuusLieben]

Type of Change

• Chore (changes to the build process or auxiliary tools)

Description

Work in progress (primarily for CI). Re-organizes our POM structure to allow modules to:

• be published more cleanly (without the project root POM being published)
• have a dedicated barebones build POM
• have a dedicated staging POM
• have a dedicated tooling/platform support POM

This also simplifies the root and assembly POMs.

How the Changes Have Been Tested

WIP

Checklist

• I have performed a self-review of my own code
• I have added tests that prove it is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Related issue number is linked in pull request title
• I have added documentation that describes my changes
• Any dependent changes have been merged and published in downstream modules
• I have rebased my branch on top of the latest develop branch

Related Issue

Closes #..