Allow multiple people to tag images and adjust timestamps in a single upload at the same time

Refer to [Poll #41](https://github.com/orgs/CulverLab/discussions/41) for more information.

Multiple people are allowed to tag images and adjust timestamps a single upload at the same time. Measures need to be in place to prevent users from trying to change the same image(s) at the same time. Users that are not allowed to edit an image will see a message informing them that they can't tag or change the timestamp of an image because another user is doing that.

Once a change is made, the change needs to be reflected for all users. When an image is finished being worked on by a user, another use can subsequently make changes

Start with Poll #41 and inspect the existing upload, image-tagging, and timestamp-editing entry points. Define how simultaneous edits are prevented, how blocked users are informed, and how completed changes reach other users; the work is done when concurrent edits to the same image are handled as described without blocking unrelated images.

Written by the indexing model from the issue text.