OOO/vacation checkbox and/or integration with Pingboard

When someone doesn't have snippets because they are on vacation it would be great if we could add a flag for that so they can easily be filtered out of the main list or at least called out as being empty because the person was OOO, not because they don't write snippets. This could be grabbed using Pingboard's API to avoid data-entry duplication.

The checkbox for this could be below the "make this snippet as private" checkbox.

Start by locating the form containing the private-snippet checkbox and the code that builds the main snippets list. Then review how person data is stored and whether Pingboard's API can provide vacation status without duplicate entry. Done means vacation status can be set or retrieved, is visible for empty snippet results, and supports filtering.

Written by the indexing model from the issue text.