Add documentation and walkthroughs

[ns-rse]

It would be useful for existing and potential users to have documentation which walks them through how to use TopoStats.

Things to cover

• Installation (awaiting publication to PyPI to facilitate and make this easier, see Build and release to PyPI #6)
• Loading the napari-TopoStats in Napari
• Loading a .topostats file.
• Loading a configuration file.
• Editing a configuration file.
• Running individual steps..
  • Filters
  • Grains
  • Others
• Viewing in 3D
• Batch processing with the current configuration (see Add button to batch process images #85)

How?

I would recommend using mkdocs to do this and leveraging the array of plugins to make it version
specific.

Examples can be found in...

• AFMReader (resulting website) -
  missing configuration for versioned documentation.
• mvdate this is a Python package @ns-rse wrote and has documented using
  mkdocs, currently the pages don't deploy anywhere but the configuration file mkdocs.yaml is the key piece of
  information along with the file structure and the repository can be cloned and the pages built and viewed
  locally. Includes configuration for versioned documentation.
• tcx2gpx this is a Python package @ns-rse wrote and has documented using
  mkdocs, currently the pages don't deploy anywhere but the configuration file mkdocs.yaml is the key piece of
  information along with the file structure and the repository can be cloned and the pages built and viewed
  locally. Includes configuration for versioned documentation.