Web devs beta

@mkenzie @jobutter I tried to add just one table from the beta averages using the web_devs scripts and made a few modifications to make_html_page.py, web_config.py and web_utils.pyto add the figures with the averages and contour plots to the table.

I uploaded the web page with those modifications on:

https://hflav-eos.web.cern.ch/hflav-eos/triangle/web_devs-beta

where the only addition is this table:

If the modifications to the scripts look ok, I could add more tables and plots in the next days so that we can show a preview of the new web page together with the updated averages and plots at the all-hands meeting at CKM.