Extract core functionality to a memory map utility independent of Jenkins

[buep]

It's been the plan for year now, we just haven't got to it.

Some of the idea is quickly drafted up here:

• Roadmap now https://github.com/Praqma/memory-map-plugin/blob/master/docs/roadmap.md
• Design: https://github.com/Praqma/memory-map-plugin/blob/master/docs/architecture.md