Feature Request: Automate Spam detection WordPress.com Forums

### What

Of late, we have noticed an increase in Spam posts and comments on https://wordpress.com/forums/. The current process is for Forums Volunteers to tag something as `Spam` to be then manually checked by an HE to mark it as Spam. Since the count of spam has gone up and this involves manual process, and there is wait time before HEs can get to this as we have other high priority tickets to handle first like sites being down etc., the spam continues to stay on the forums longer than before.

It will be helpful to scan the forums automatically to detect spam posts, comments, threads and close them to save both Volunteer and HE time and keep our forums clean.

### Why

As shared above this will streamline the process to keep our forums free of spam.

### How

A potential solution is already being discussed on this P2 but this had to be paused. I think that's a good solution to tackle spam.
> pfnqB3-bu-p2

Start with the paused pfnqB3-bu-p2 discussion referenced in the issue, since no repository files, tests, or entry points are identified here. Done would mean an agreed implementation that automatically detects and closes spam posts, comments, and threads on the WordPress.com forums, with the moderation workflow defined.

Written by the indexing model from the issue text.