Adjust how average data is displayed for a single page

[amfred]

We need to be able to see how different sets of pages are performing over time. Currently, when Page Lab shows the average data for a specific web page, it's averaging all of the results it has collected since the time the page was registered with the system. The longer a page has been tracked, the harder it will be to see the effect of changes made to the page and get feedback on how they positively or negatively affected performance.

I recommend making these updates: When viewing the details for one page's performance data, use a 30-day trailing average for the performance score as the basic display.
Also show these additional calculated metrics:

• 10 percentile and 90th percentile performance scores over the last 30 days.
• 1-week trailing average for the performance score (to get even faster feedback on changes).