Generate monthly Onion report

[jamesgorrie]

We get this information from Fastly and stored in S3.

It should contain

• [ ] How many pageviews via onion service

[rhiannareechaye]

As per our triaging, this is a high impact issue so ideally we should look at it

[alinaboghiu]

@ioannakok FYI this ticket already exists :)

[ioannakok]

This might depend on:

• https://github.com/guardian/dotcom-onion-platform/issues/22