Revisions to documentation tutorials overview and content and addition of team page

[jason-bentley]

This PR

1. Revises and tidy’s up the three tutorial notebooks: classification with FACET, regression with FACET and the bite-sized simulation study.
2. Revised and expanded the tutorial.rst for improved layout of the Tutorials page in the documentation
3. Adds a FACET Team page with place holders for Team members photos once ready (future PR)

To run

Please navigate to sphinx and run documentation build as usual python make.py html.

Expected outputs

You should see the revised tutorials page:

As well as the new team page:

[mgelsm]

Runs successfully