In activity table, remove `user_id` and add `sensitive` #127

Tested and works as expected for private message and comment create.

Gitea is giving 404 when commenting on the diff...

About the changes in activity_queue.rs, right now it works fine like that because all private message and follow activities go through send_activity_single_dest(). But we will have to adjust the other methods once we add private communities etc.

In the inboxes, I just marked everything as sensitive, because that value is completely ignored for remote activities. To set it properly, we would have to move insert_activity() down into the specific activity handlers for each type, and thats just not worth the effort.

Gitea is giving 404 when commenting on the diff...

I got the same, no idea why.

But we will have to adjust the other methods once we add private communities etc.

That's fine. Up to you whether to add a comment there mentioning that or not.

Once this passes I'll merge.

I think you forgot to add the migration, so the tests are failing.

Damn it, every time. I'm so used to typing git commit -a and assuming that it takes care of everything. Fixed.

Looks good, everything passed. The down migration is missing the foreign key relation but its not an important column anyway.