[TASK] Convert walked fs hierarchy into partition graph

[kurtlawrence]

Goal

Using the structure build from #175, add each item into the partition graph structure.

Aspects to Develop

• Testable in memory
• Tests for item name clashes within a partition
• Items do not need to be parsed/compiled, this can be done lazily (however the code snippets would need to be stored)
• Check for partition name validity