add api endpoint to retrieve authenticated user's reports

[tybug]

There's currently no way to see the reports you've filed through the website. Adding a page to see all your reports would be ideal, but I'm going to guess that's too much effort to add in the near future, so an api endpoint is the next best thing.

Without this endpoint (or a dedicated reports page), people who frequently report users or scores through the website have no way to track how many reports they've made, who they've reported, or the text of their reports, unless they record each one themselves in a personal text file or document.

This would also enable third party applications to step in and fill the role of #4210, for instance, by checking recently reported users to see if they have been restricted and alerting the user if so.

[peppy]

I'm not sure how much I agree with this.

Reports for the time being are considered something which do not generate any kind of user response, nor are reports considered to be attached to users (once arriving at our end they should be considered anonymous, for instance we do not include them in GDPR data exports as user data).