[IMPR] Rank contributors by month
Improving the contributors ranking feature by adding
a relevant a route, adding related CSS, and some test methods.
- Adding a call-to-action link on pages that display monthly results
- Applying related CSS customization
- New route REST endpoint for getting a sorted monthly list of contributors
- New layout displaying montlhy list of contributor
- Reordering methods in awmdstats/app.py alphabetically