regression reporter: editable regression status data

**As a regression reporter, I want to be able to add status data to a regression so we can keep track of it.**

## Background

While exposing the information of a regression to the developers is useful, there should be a way to add data to the KernelCI database in the other direction, that is, from the users to the CI system.

Once someone starts working on a regression, it'd be useful to mark it as "claimed" or "in-progress" so that it's not reported anymore and anyone checking the regression in the KernelCI frontend can easily check who's working on it and participate on it. Same thing once the regression is finally fixed, or if it's found to be a false positive. Currently we don't have any of this information and every time a regression is reported we can't be sure if someone's working on it or if it was fixed already or if someone concluded it's not a real regression, and a lot of time is wasted.

The issue names the KernelCI database and frontend but no files, tests, or entry points. First map where regression records are stored and displayed, then clarify the status and ownership model. Done should make claimed, in-progress, fixed, and false-positive states visible and identify who is working on a regression.

Written by the indexing model from the issue text.