Create a github workflow/bot for parsing diagnostics in issues

[agittins]

When folks upload a "download diagnostics" to an issue, it would be helpful for a workflow to parse it and summarize some info in a subsequent post.

In particular, some of the stats being worked on in #363 and other useful info as things evolve.

This might be a good feature for someone who isn't across the wider project yet, but is keen to dig into something to start with.

• Parse the json from diagnostics
• Identify vital stats such as those discussed in FR: Add Diagnostic Entities on Scanners #363 and surface them in a comment
• If a debug-enabled log file is included:
  • Possibly anonamise and replace the log file (it includes mac and IP addresses)
  • parse out:
    • For each scanner, stats on adverts-per-second
    • Summaries of adverts from each MAC address
    • Identify exceptions/errors, possibly grouping them along with counts and stats