Separate out Ordered Tracing from dnaTracing.py

[Max-Gamill]

This PR adds the "ordered_tracing.py" module to TopoStats which does the sole function of ordering the disordered traces either as TopoStats normally does, or via NodeStats if requested / possible.

2 new diagnostic images are produced -> an over/under labeled image, and labeled molecule image. 1 new core image is added -> an ordered trace image where the pixels are coloured rainbow(ish) along their order. (Currently) 1 new stat is added to grainstats -> num_mols. Saves molecule traces, height and distance profiles and molecule stats (circular: T/F) to the .topostats file.

*Note: For some reason, trying to rebase from 800-btr-nodestats2 automatically merges some sections of run_nodestats and run_ordered_tracing together (possibly because they look similar to git) causing it to revert many of the changes |-> because rebasing is done commit by commit.

[Max-Gamill]

@ns-rse Addressed most of the comments, others I'd like some best practice advice on :)

[Max-Gamill]

This has been added in #889