Support Forums: Improve topic report functionality

[Clorith]

This will be an overarching task of multiple enhancements that together will make things better in the grand scheme of things.

The current state of a reported topic is a mix between using the modlook tag, and storing the reporter details in postmeta and displaying it in the sidebar.

Although a great initial implementation, over time some other needs and necessities have shown them selves.

I'm proposing we retain the sidebar report area, but make it more user friendly (we do get users joining Slack asking where to report a topic or review for example).

To improve discoveryability here:

• Always show the report area, but make it context aware, if you can't report a topic, show why (topic is closed, only logged in users may report a topic etc)
• Add some kind of visual indicator, something simple but effective like making the flag icon "report this red", when there's little to no color used elsewhere?

For the reports them selves, move away from postmeta, and instead inject the report message as a custom comment type, only visible to those with moderator capabilities. This also brings multiple benefits to the table;

• Easier to read, compared to the compacted sidebar area
• Puts the report into context in the timeline of a thread
• Allows us to pull data in user profiles on the reports they make, to make it easier to identify potential new members for the team

There is one drawback to moving it out of postmeta, I'd call it a minor inconvenience that's easy to solve, more so than a drawback. A migration script should be ran to pull existing reports out of postmeta and added as post types as well. This should work well to backfill, since we have author data, report reason, and a timestamp, all that's needed to fit it into the timeline.

Those were the easy tasks, next up some improvements for privacy and user security.

Privacy related, we tell users that their report is anonymous, only moderators can see what they reported, and that they reported, a topic (unless they manually added the modlook tag), when in reality if a mod doesn't understand the report, the user will more often than not be called out in the #forums channel on Slack.

Let's improve on this, and add an inline action to the report comment type, allowing someone with moderator caps to reply directly to the reporter. This would be a one-way communication tool, it would still register who wrote the reply for our own sake (since this would be hidden to non-moderator users), but it would always send a notification to the reporter about the outcome of their report (I think this might be a benefit regardless if you need to clarify something, or if action has been taken, let the reporter know that their report was seen and acted on in one way or another).

The benefit of this kind of notification is that we can set the sender, let the message be sent by the "WordPress.org Forums" or similar, taking the moderator out of the equation in a "we are one" kind of scenario. This does remove a little bit of the human element, but it also removes a huge factor for retributions against individual moderators if the user doesn't know which moderator acted on their topic.

[fierevere]

Implementing this ticket will obsolete
related #5708