[MODERATION] user blocking

- Add the ability to block a user via their profile page.
- This will unstar their repositories and visa versa.
- Blocked users cannot create issues or pull requests on your the doer's repositories (mind that this is not the case for organizations).
- Blocked users cannot comment on the doer's opened issues or pull requests.
- Blocked users cannot add reactions to doer's comments.
- Blocked users cannot cause a notification trough mentioning the doer.

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/540
(cherry picked from commit 687d852480)
(cherry picked from commit 0c32a4fde5)
(cherry picked from commit 1791130e3c)
(cherry picked from commit 37858b7e8f)

services/user/delete.go

@@ -90,6 +90,8 @@ func deleteUser(ctx context.Context, u *user_model.User, purge bool) (err error)
 		&pull_model.AutoMerge{DoerID: u.ID},
 		&pull_model.ReviewState{UserID: u.ID},
 		&user_model.Redirect{RedirectUserID: u.ID},
+		&user_model.BlockedUser{BlockID: u.ID},
+		&user_model.BlockedUser{UserID: u.ID},
 	); err != nil {
 		return fmt.Errorf("deleteBeans: %w", err)
 	}